How do you define a method within a class?

To define a method within a class, the correct approach is to define a function inside the class. In the context of object-oriented programming, a method is specifically a function that is associated with an object. When you declare a function within a class definition, it becomes a method that can operate on instances (objects) of that class.

Methods typically have access to the class instance through the self parameter (in Python, for instance), which allows them to access the instance's attributes and other methods. This encapsulation is fundamental to object-oriented design as it allows methods to manipulate the internal state of the object encapsulated within the class.

Declaring a method outside the class, using global variables, or utilizing a special keyword does not constitute defining a method within a class. These options do not associate the function with the object and miss the encapsulation and structure that a class provides. Thus, defining a function inside the class is essential to properly establish its role as a method that relates to the class instance.