C# Design Patterns MCQ Questions with Answers – Page 2 (Latest 2026)

Q51. Which statement about Chain of Responsibility is most accurate?

A. Pass requests along a chain until handled. B. A pure command. C. Single handler always. D. A pure observer.

Select an answer to check.

Answer: Pass requests along a chain until handled.

Here, Pass requests along a chain until handled. is the right choice. Decouples sender and handler. It aligns directly with what the question asks about which statement about chain of responsibility is most. Competing choices sound plausible, but they miss the key condition.

Q52. How is Chain of Responsibility best characterized?

A. A pure command. B. A pure observer. C. Pass requests along a chain until handled. D. Single handler always.

Select an answer to check.

Answer: Pass requests along a chain until handled.

In this case, Pass requests along a chain until handled. is correct. Decouples sender and handler. It aligns directly with what the question asks about how is chain of responsibility best characterized. Competing choices sound plausible, but they miss the key condition.

Q53. Which option best describes Command in C#/.NET?

A. A pure mediator. B. A pure observer. C. Encapsulates a request as an object. D. A pure event.

Select an answer to check.

Answer: Encapsulates a request as an object.

The best option here is Encapsulates a request as an object.. Enables undo/redo, queuing. It aligns directly with what the question asks about which option best describes command in c#/.net. Competing choices sound plausible, but they miss the key condition.

Q54. What is the primary purpose of Command?

A. A pure mediator. B. A pure observer. C. A pure event. D. Encapsulates a request as an object.

Select an answer to check.

Answer: Encapsulates a request as an object.

For this question, Encapsulates a request as an object. is correct. Enables undo/redo, queuing. It aligns directly with what the question asks about what is the primary purpose of command. Competing choices sound plausible, but they miss the key condition.

Q55. Which statement about Command is most accurate?

A. A pure mediator. B. A pure event. C. Encapsulates a request as an object. D. A pure observer.

Select an answer to check.

Answer: Encapsulates a request as an object.

Encapsulates a request as an object. is the correct answer here. Enables undo/redo, queuing. It aligns directly with what the question asks about which statement about command is most accurate. Competing choices sound plausible, but they miss the key condition.

Q56. How is Command best characterized?

A. A pure mediator. B. A pure observer. C. Encapsulates a request as an object. D. A pure event.

Select an answer to check.

Answer: Encapsulates a request as an object.

Here, Encapsulates a request as an object. is the right choice. Enables undo/redo, queuing. This matches the core idea being tested around how is command best characterized. Competing choices sound plausible, but they miss the key condition.

Q57. Which option best describes Iterator in C#/.NET?

A. A pure observer. B. A pure mediator. C. Sequential access without exposing structure. D. A pure visitor.

Select an answer to check.

Answer: Sequential access without exposing structure.

In this case, Sequential access without exposing structure. is correct. C# uses IEnumerator/foreach. This matches the core idea being tested around which option best describes iterator in c#/.net. Competing choices sound plausible, but they miss the key condition.

Q58. What is the primary purpose of Iterator?

A. A pure mediator. B. A pure observer. C. A pure visitor. D. Sequential access without exposing structure.

Select an answer to check.

Answer: Sequential access without exposing structure.

The best option here is Sequential access without exposing structure.. C# uses IEnumerator/foreach. This matches the core idea being tested around what is the primary purpose of iterator. Competing choices sound plausible, but they miss the key condition.

Q59. Which statement about Iterator is most accurate?

A. A pure observer. B. A pure mediator. C. Sequential access without exposing structure. D. A pure visitor.

Select an answer to check.

Answer: Sequential access without exposing structure.

For this question, Sequential access without exposing structure. is correct. C# uses IEnumerator/foreach. This matches the core idea being tested around which statement about iterator is most accurate. Competing choices sound plausible, but they miss the key condition.

Q60. How is Iterator best characterized?

A. A pure visitor. B. A pure mediator. C. Sequential access without exposing structure. D. A pure observer.

Select an answer to check.

Answer: Sequential access without exposing structure.

Sequential access without exposing structure. is the correct answer here. C# uses IEnumerator/foreach. This matches the core idea being tested around how is iterator best characterized. Competing choices sound plausible, but they miss the key condition.

Q61. Which option best describes Mediator in C#/.NET?

A. Pure command. B. Pure visitor. C. Centralizes complex communications. D. Pure observer.

Select an answer to check.

Answer: Centralizes complex communications.

Here, Centralizes complex communications. is the right choice. Reduces direct coupling. That is exactly the concept behind which option best describes mediator in c#/.net in this context. Competing choices sound plausible, but they miss the key condition.

Q62. What is the primary purpose of Mediator?

A. Centralizes complex communications. B. Pure visitor. C. Pure command. D. Pure observer.

Select an answer to check.

Answer: Centralizes complex communications.

In this case, Centralizes complex communications. is correct. Reduces direct coupling. That is exactly the concept behind what is the primary purpose of mediator in this context. Competing choices sound plausible, but they miss the key condition.

Q63. Which statement about Mediator is most accurate?

A. Centralizes complex communications. B. Pure observer. C. Pure visitor. D. Pure command.

Select an answer to check.

Answer: Centralizes complex communications.

The best option here is Centralizes complex communications.. Reduces direct coupling. That is exactly the concept behind which statement about mediator is most accurate in this context. Competing choices sound plausible, but they miss the key condition.

Q64. How is Mediator best characterized?

A. Centralizes complex communications. B. Pure observer. C. Pure command. D. Pure visitor.

Select an answer to check.

Answer: Centralizes complex communications.

For this question, Centralizes complex communications. is correct. Reduces direct coupling. That is exactly the concept behind how is mediator best characterized in this context. Competing choices sound plausible, but they miss the key condition.

Q65. Which option best describes Memento in C#/.NET?

A. A pure observer. B. A pure command. C. Capture/restore object state. D. A pure visitor.

Select an answer to check.

Answer: Capture/restore object state.

Capture/restore object state. is the correct answer here. Implements undo. That is exactly the concept behind which option best describes memento in c#/.net in this context. Competing choices sound plausible, but they miss the key condition.

Q66. What is the primary purpose of Memento?

A. Capture/restore object state. B. A pure command. C. A pure visitor. D. A pure observer.

Select an answer to check.

Answer: Capture/restore object state.

Here, Capture/restore object state. is the right choice. Implements undo. It fits the requirement in the prompt about what is the primary purpose of memento. Competing choices sound plausible, but they miss the key condition.

Q67. Which statement about Memento is most accurate?

A. A pure observer. B. Capture/restore object state. C. A pure visitor. D. A pure command.

Select an answer to check.

Answer: Capture/restore object state.

In this case, Capture/restore object state. is correct. Implements undo. It fits the requirement in the prompt about which statement about memento is most accurate. Competing choices sound plausible, but they miss the key condition.

Q68. How is Memento best characterized?

A. A pure command. B. A pure observer. C. Capture/restore object state. D. A pure visitor.

Select an answer to check.

Answer: Capture/restore object state.

The best option here is Capture/restore object state.. Implements undo. It fits the requirement in the prompt about how is memento best characterized. Competing choices sound plausible, but they miss the key condition.

Q69. Which option best describes Observer in C#/.NET?

A. One-to-many notifications on state change. B. A pure mediator. C. A pure command. D. A pure visitor.

Select an answer to check.

Answer: One-to-many notifications on state change.

For this question, One-to-many notifications on state change. is correct. Events implement this. It fits the requirement in the prompt about which option best describes observer in c#/.net. Competing choices sound plausible, but they miss the key condition.

Q70. What is the primary purpose of Observer?

A. One-to-many notifications on state change. B. A pure mediator. C. A pure command. D. A pure visitor.

Select an answer to check.

Answer: One-to-many notifications on state change.

One-to-many notifications on state change. is the correct answer here. Events implement this. It fits the requirement in the prompt about what is the primary purpose of observer. Competing choices sound plausible, but they miss the key condition.

Q71. Which statement about Observer is most accurate?

A. One-to-many notifications on state change. B. A pure visitor. C. A pure mediator. D. A pure command.

Select an answer to check.

Answer: One-to-many notifications on state change.

Here, One-to-many notifications on state change. is the right choice. Events implement this. This is the most accurate statement for which statement about observer is most accurate. Competing choices sound plausible, but they miss the key condition.

Q72. How is Observer best characterized?

A. A pure mediator. B. A pure visitor. C. One-to-many notifications on state change. D. A pure command.

Select an answer to check.

Answer: One-to-many notifications on state change.

In this case, One-to-many notifications on state change. is correct. Events implement this. This is the most accurate statement for how is observer best characterized. Competing choices sound plausible, but they miss the key condition.

Q73. Which option best describes State in C#/.NET?

A. Iterator pattern. B. Strategy pattern. C. Visitor pattern. D. Object alters behavior when its state changes.

Select an answer to check.

Answer: Object alters behavior when its state changes.

The best option here is Object alters behavior when its state changes.. Encapsulates state-specific behavior. This is the most accurate statement for which option best describes state in c#/.net. Competing choices sound plausible, but they miss the key condition.

Q74. What is the primary purpose of State?

A. Object alters behavior when its state changes. B. Strategy pattern. C. Iterator pattern. D. Visitor pattern.

Select an answer to check.

Answer: Object alters behavior when its state changes.

For this question, Object alters behavior when its state changes. is correct. Encapsulates state-specific behavior. This is the most accurate statement for what is the primary purpose of state. Competing choices sound plausible, but they miss the key condition.

Q75. Which statement about State is most accurate?

A. Visitor pattern. B. Iterator pattern. C. Object alters behavior when its state changes. D. Strategy pattern.

Select an answer to check.

Answer: Object alters behavior when its state changes.

Object alters behavior when its state changes. is the correct answer here. Encapsulates state-specific behavior. This is the most accurate statement for which statement about state is most accurate. Competing choices sound plausible, but they miss the key condition.

Q76. How is State best characterized?

A. Object alters behavior when its state changes. B. Iterator pattern. C. Strategy pattern. D. Visitor pattern.

Select an answer to check.

Answer: Object alters behavior when its state changes.

Here, Object alters behavior when its state changes. is the right choice. Encapsulates state-specific behavior. It aligns directly with what the question asks about how is state best characterized. The remaining choices fail because they don’t satisfy the full definition.

Q77. Which option best describes Strategy in C#/.NET?

A. Bridge pattern. B. State pattern. C. Visitor pattern. D. Family of interchangeable algorithms.

Select an answer to check.

Answer: Family of interchangeable algorithms.

In this case, Family of interchangeable algorithms. is correct. Inject behavior at runtime. It aligns directly with what the question asks about which option best describes strategy in c#/.net. The remaining choices fail because they don’t satisfy the full definition.

Q78. What is the primary purpose of Strategy?

A. Family of interchangeable algorithms. B. State pattern. C. Bridge pattern. D. Visitor pattern.

Select an answer to check.

Answer: Family of interchangeable algorithms.

The best option here is Family of interchangeable algorithms.. Inject behavior at runtime. It aligns directly with what the question asks about what is the primary purpose of strategy. The remaining choices fail because they don’t satisfy the full definition.

Q79. Which statement about Strategy is most accurate?

A. Family of interchangeable algorithms. B. Visitor pattern. C. State pattern. D. Bridge pattern.

Select an answer to check.

Answer: Family of interchangeable algorithms.

For this question, Family of interchangeable algorithms. is correct. Inject behavior at runtime. It aligns directly with what the question asks about which statement about strategy is most accurate. The remaining choices fail because they don’t satisfy the full definition.

Q80. How is Strategy best characterized?

A. Family of interchangeable algorithms. B. State pattern. C. Visitor pattern. D. Bridge pattern.

Select an answer to check.

Answer: Family of interchangeable algorithms.

Family of interchangeable algorithms. is the correct answer here. Inject behavior at runtime. It aligns directly with what the question asks about how is strategy best characterized. The remaining choices fail because they don’t satisfy the full definition.

Q81. Which option best describes Template Method in C#/.NET?

A. Visitor pattern. B. Command pattern. C. Defines algorithm skeleton; steps in subclasses. D. Strategy pattern.

Select an answer to check.

Answer: Defines algorithm skeleton; steps in subclasses.

Here, Defines algorithm skeleton; steps in subclasses. is the right choice. Inheritance-based variation. This matches the core idea being tested around which option best describes template method in c#/.net. The remaining choices fail because they don’t satisfy the full definition.

Q82. What is the primary purpose of Template Method?

A. Command pattern. B. Visitor pattern. C. Defines algorithm skeleton; steps in subclasses. D. Strategy pattern.

Select an answer to check.

Answer: Defines algorithm skeleton; steps in subclasses.

In this case, Defines algorithm skeleton; steps in subclasses. is correct. Inheritance-based variation. This matches the core idea being tested around what is the primary purpose of template method. The remaining choices fail because they don’t satisfy the full definition.

Q83. Which statement about Template Method is most accurate?

A. Visitor pattern. B. Command pattern. C. Defines algorithm skeleton; steps in subclasses. D. Strategy pattern.

Select an answer to check.

Answer: Defines algorithm skeleton; steps in subclasses.

The best option here is Defines algorithm skeleton; steps in subclasses.. Inheritance-based variation. This matches the core idea being tested around which statement about template method is most accurate. The remaining choices fail because they don’t satisfy the full definition.

Q84. How is Template Method best characterized?

A. Visitor pattern. B. Strategy pattern. C. Command pattern. D. Defines algorithm skeleton; steps in subclasses.

Select an answer to check.

Answer: Defines algorithm skeleton; steps in subclasses.

For this question, Defines algorithm skeleton; steps in subclasses. is correct. Inheritance-based variation. This matches the core idea being tested around how is template method best characterized. The remaining choices fail because they don’t satisfy the full definition.

Q85. Which option best describes Visitor in C#/.NET?

A. Add operations to objects without modifying them. B. Command pattern. C. Iterator pattern. D. Observer pattern.

Select an answer to check.

Answer: Add operations to objects without modifying them.

Add operations to objects without modifying them. is the correct answer here. Useful for AST processing. This matches the core idea being tested around which option best describes visitor in c#/.net. The remaining choices fail because they don’t satisfy the full definition.

Q86. What is the primary purpose of Visitor?

A. Add operations to objects without modifying them. B. Iterator pattern. C. Command pattern. D. Observer pattern.

Select an answer to check.

Answer: Add operations to objects without modifying them.

Here, Add operations to objects without modifying them. is the right choice. Useful for AST processing. That is exactly the concept behind what is the primary purpose of visitor in this context. The remaining choices fail because they don’t satisfy the full definition.

Q87. Which statement about Visitor is most accurate?

A. Iterator pattern. B. Command pattern. C. Observer pattern. D. Add operations to objects without modifying them.

Select an answer to check.

Answer: Add operations to objects without modifying them.

In this case, Add operations to objects without modifying them. is correct. Useful for AST processing. That is exactly the concept behind which statement about visitor is most accurate in this context. The remaining choices fail because they don’t satisfy the full definition.

Q88. How is Visitor best characterized?

A. Iterator pattern. B. Observer pattern. C. Command pattern. D. Add operations to objects without modifying them.

Select an answer to check.

Answer: Add operations to objects without modifying them.

The best option here is Add operations to objects without modifying them.. Useful for AST processing. That is exactly the concept behind how is visitor best characterized in this context. The remaining choices fail because they don’t satisfy the full definition.

Q89. Which option best describes Repository pattern in C#/.NET?

A. A pure singleton. B. A pure logging pattern. C. Abstracts data access behind an interface. D. A factory pattern.

Select an answer to check.

Answer: Abstracts data access behind an interface.

For this question, Abstracts data access behind an interface. is correct. Enables testability. That is exactly the concept behind which option best describes repository pattern in c#/.net in this context. The remaining choices fail because they don’t satisfy the full definition.

Q90. What is the primary purpose of Repository pattern?

A. A pure singleton. B. A factory pattern. C. Abstracts data access behind an interface. D. A pure logging pattern.

Select an answer to check.

Answer: Abstracts data access behind an interface.

Abstracts data access behind an interface. is the correct answer here. Enables testability. That is exactly the concept behind what is the primary purpose of repository pattern in this context. The remaining choices fail because they don’t satisfy the full definition.

Q91. Which statement about Repository pattern is most accurate?

A. Abstracts data access behind an interface. B. A pure singleton. C. A factory pattern. D. A pure logging pattern.

Select an answer to check.

Answer: Abstracts data access behind an interface.

Here, Abstracts data access behind an interface. is the right choice. Enables testability. It fits the requirement in the prompt about which statement about repository pattern is most accurate. The remaining choices fail because they don’t satisfy the full definition.

Q92. How is Repository pattern best characterized?

A. A pure logging pattern. B. A pure singleton. C. Abstracts data access behind an interface. D. A factory pattern.

Select an answer to check.

Answer: Abstracts data access behind an interface.

In this case, Abstracts data access behind an interface. is correct. Enables testability. It fits the requirement in the prompt about how is repository pattern best characterized. The remaining choices fail because they don’t satisfy the full definition.

Q93. Which option best describes Unit of Work in C#/.NET?

A. A pure factory. B. Tracks changes and commits as one transaction. C. A pure observer. D. A pure repository.

Select an answer to check.

Answer: Tracks changes and commits as one transaction.

The best option here is Tracks changes and commits as one transaction.. Often paired with repositories. It fits the requirement in the prompt about which option best describes unit of work in. The remaining choices fail because they don’t satisfy the full definition.

Q94. What is the primary purpose of Unit of Work?

A. A pure repository. B. Tracks changes and commits as one transaction. C. A pure factory. D. A pure observer.

Select an answer to check.

Answer: Tracks changes and commits as one transaction.

For this question, Tracks changes and commits as one transaction. is correct. Often paired with repositories. It fits the requirement in the prompt about what is the primary purpose of unit of. The remaining choices fail because they don’t satisfy the full definition.

Q95. Which statement about Unit of Work is most accurate?

A. A pure factory. B. A pure repository. C. A pure observer. D. Tracks changes and commits as one transaction.

Select an answer to check.

Answer: Tracks changes and commits as one transaction.

Tracks changes and commits as one transaction. is the correct answer here. Often paired with repositories. It fits the requirement in the prompt about which statement about unit of work is most. The remaining choices fail because they don’t satisfy the full definition.

Q96. How is Unit of Work best characterized?

A. A pure observer. B. A pure repository. C. A pure factory. D. Tracks changes and commits as one transaction.

Select an answer to check.

Answer: Tracks changes and commits as one transaction.

Here, Tracks changes and commits as one transaction. is the right choice. Often paired with repositories. This is the most accurate statement for how is unit of work best characterized. The remaining choices fail because they don’t satisfy the full definition.

Q97. Which option best describes Dependency Injection in C#/.NET?

A. Provide collaborators rather than constructing them. B. Service Locator only. C. Singleton only. D. Factory only.

Select an answer to check.

Answer: Provide collaborators rather than constructing them.

In this case, Provide collaborators rather than constructing them. is correct. Encourages testability. This is the most accurate statement for which option best describes dependency injection in c#/.net. The remaining choices fail because they don’t satisfy the full definition.

Q98. What is the primary purpose of Dependency Injection?

A. Service Locator only. B. Provide collaborators rather than constructing them. C. Singleton only. D. Factory only.

Select an answer to check.

Answer: Provide collaborators rather than constructing them.

The best option here is Provide collaborators rather than constructing them.. Encourages testability. This is the most accurate statement for what is the primary purpose of dependency injection. The remaining choices fail because they don’t satisfy the full definition.

Q99. Which statement about Dependency Injection is most accurate?

A. Singleton only. B. Service Locator only. C. Provide collaborators rather than constructing them. D. Factory only.

Select an answer to check.

Answer: Provide collaborators rather than constructing them.

For this question, Provide collaborators rather than constructing them. is correct. Encourages testability. This is the most accurate statement for which statement about dependency injection is most accurate. The remaining choices fail because they don’t satisfy the full definition.

Q100. How is Dependency Injection best characterized?

A. Factory only. B. Singleton only. C. Provide collaborators rather than constructing them. D. Service Locator only.

Select an answer to check.

Answer: Provide collaborators rather than constructing them.

Provide collaborators rather than constructing them. is the correct answer here. Encourages testability. This is the most accurate statement for how is dependency injection best characterized. The remaining choices fail because they don’t satisfy the full definition.