In C sharp syntax, how do you declare that one class inherits from another base class in order to reuse and extend its members?

Introduction / Context:
Inheritance is a core concept of object oriented programming, and C sharp provides a specific syntax to declare that a class derives from another class. This allows the derived class to reuse and extend the properties, methods, and behavior of the base class. Many languages use different keywords such as extends or inherits, so it is important to remember the correct C sharp specific syntax. This question tests your familiarity with that syntax.

Given Data / Assumptions:

• We are working with C sharp, not Java or Visual Basic.
• A base class already exists, and we want to create a derived class that inherits from it.
• We want to reuse and extend the functionality of the base class in an object oriented way.
• The question asks for the syntax used in the class declaration line.

Concept / Approach:
In C sharp, the colon character is used in class declarations to specify both inheritance and interface implementation. When listing types after the colon, the first type must be the single base class (if any), and any subsequent types are interfaces implemented by the class. Unlike languages such as Java that use the extends keyword or Visual Basic that uses Inherits, C sharp keeps the syntax concise by using colon and a list of types. For example, class MyForm : Form declares that MyForm inherits from the Form base class provided by Windows Forms.

Step-by-Step Solution:
Step 1: Recall that C sharp uses the colon symbol in class declarations to introduce base types. Step 2: Recognize that the correct pattern for class inheritance is class DerivedClass : BaseClass. Step 3: Understand that the keywords extends and inherits are not used in C sharp for classes, even though they appear in other languages. Step 4: Choose the option that shows the colon based syntax with DerivedClass followed by a colon and the BaseClass name.

Verification / Alternative check:
If you create a simple C sharp file and declare class Animal followed by class Dog : Animal, the code compiles successfully and Dog gains access to the public and protected members of Animal. If you instead try class Dog extends Animal, the C sharp compiler reports an error because extends is not a valid keyword in this context. The same happens with inherits as a keyword. This hands on check confirms that the colon syntax is the correct way to express inheritance in C sharp.

Why Other Options Are Wrong:
Option B uses extends, which is a keyword in Java but not in C sharp for inheritance. Option C uses inherits, which belongs to Visual Basic syntax, not C sharp. Option D uses implements, a keyword that some languages use for interfaces, but in C sharp there is no implements keyword in the class declaration. Option E uses uses, which is not a C sharp keyword for inheritance or interfaces. None of these options match the actual syntax used by the C sharp compiler.

Common Pitfalls:
A common pitfall is mixing up syntax from different languages, especially if you work with Java, C sharp, and Visual Basic in the same environment. Another mistake is forgetting that the first type after the colon must be the base class if one exists, and that only one base class is allowed. Additional types listed after the base class are treated as interfaces, which follow slightly different rules. By remembering the concise pattern class DerivedClass : BaseClass, you avoid syntax errors and communicate inheritance intentions clearly in your code.

Final Answer:
class DerivedClass : BaseClass