Final answer:
No, a class that requires modifications with each extension does not follow the Open-Closed Principle (OCP). The principle advocates for extending behavior without altering existing code, using design patterns that support this kind of extensibility.
Step-by-step explanation:
If a class requires modifications every time it is extended, then it does not adhere to the Open-Closed Principle (OCP). The OCP is one of the five SOLID principles of object-oriented design, which states that software entities (classes, modules, functions, etc.) should be open for extension but closed for modification. This means that the behavior of a module can be extended without modifying its source code.
In a practical sense, adherence to the OCP typically involves using interfaces and/or abstract classes to allow new functionality to be added without changing existing code. If you find that you are constantly needing to change a class when extending it, this is a sign that the class may not be well-designed with OCP in mind. Instead, consider using patterns like strategy, template method, or decorator to extend behavior in a way that does not require altering the original class.
Therefore, the correct answer is b. No, the class does not adhere to the Open-Closed Principle if it needs to be modified every time it is extended. This violates the core idea that entities should remain closed for modification, meaning that their existing source code should not be altered when new features are needed.