Which of the following best describes polymorphism in object-oriented programming?

Polymorphism in object-oriented programming is best described by the ability to define multiple methods with the same name. This is a fundamental concept in OOP that allows methods to be defined in different ways, enabling objects of different classes to be treated as objects of a common superclass. When a method is called, the appropriate method for the actual object type is executed, which can lead to more flexible and reusable code.

This capability is commonly achieved through method overriding (where a subclass provides a specific implementation of a method that is already defined in its superclass) and method overloading (where multiple methods with the same name exist in the same class but differ in parameter lists).

Other options do not accurately capture the essence of polymorphism. While creating random objects, combining data and functions, and restricting access to certain parts of objects are important aspects of object-oriented programming, they relate to different concepts such as object instantiation, encapsulation, and information hiding, rather than polymorphism itself.