In object-oriented design, a base class typically provides what for derived classes?

• A. Implementing all methods so derived classes need no overrides.
• B. Deriving common behavior and properties for child classes.
• C. Storing data in global scope.
• D. Preventing inheritance.

Answer: (B)

Base classes capture the common state and behavior that multiple derived classes share. By putting this functionality in one place, derived classes automatically reuse it, which reduces duplication and keeps changes centralized. They can still specialize by adding new members or by overriding methods to tailor how they work while still conforming to the same interface. This arrangement also supports polymorphism, since code can work with the base type while objects may actually be instances of any derived type. Often the base class provides default implementations for shared features and may declare abstract or virtual methods that derived classes override or extend. The alternative patterns aren’t as fitting here: a base class isn’t intended to force every method to be implemented there, nor is it about storing data in global scope. And while some languages let you seal a base class to prevent inheritance, the primary role of a base class is to be extended to share common features.