What is polymorphism in programming?

Polymorphism in programming refers to the ability of different classes to be treated as instances of the same class through a shared interface. This concept allows different objects to respond to the same method call in different ways, leveraging the platform of method overriding or method overloading.

The correct answer relates specifically to defining multiple versions of a method, which is often achieved through method overloading and method overriding. Method overloading is when a single method name is used for multiple purposes based on different parameter types or numbers within the same class. Method overriding occurs when a subclass provides a specific implementation of a method already defined in its superclass. Both of these practices embody the essence of polymorphism, where the same method name can perform different tasks depending on the context in which it is called.

This concept facilitates flexibility and integration within object-oriented programming, allowing developers to write code that is more reusable and easier to maintain. Polymorphism enables a programmer to invoke a method in a subclass without needing to know the details of the subclass, fostering easier expansion or modification of software.

The other options listed may describe important features of object-oriented programming but do not capture the full scope of what polymorphism entails in the context of method definitions and their utilization across different classes.