Oops Concept

Object-Oriented Programming (OOP) is based on several key principles:
- Encapsulation (A) is the concept of bundling data and methods that operate on that data within a single unit (class), hiding the implementation details from outside access.
- Inheritance (B) allows one class to inherit properties and behaviors from another, promoting code reuse.
- Polymorphism (C) allows objects of different types to be treated as objects of a common super type, typically allowing for method overriding.
- Compilation (D) is not a principle of OOP, but rather a process that converts high-level code into machine-readable code. It is not directly related to OOP principles.
Thus, the correct answer is (D), Compilation.

In object-oriented programming (OOP), encapsulation refers to the practice of bundling the data (variables) and the methods (functions) that operate on that data into a single unit called a class. It also involves restricting access to some of the object's components, which is often done by making some properties or methods private, thereby hiding the internal implementation details from the outside world.
- Combining data and methods into a single unit (A) is a general description of encapsulation, but the focus is on hiding implementation details (B).
- Inheriting properties from a parent class (C) refers to inheritance, not encapsulation.
- Allowing multiple forms of a method (D) refers to polymorphism, not encapsulation.
Thus, the correct answer is (B).