Where is a function parameter accessible when defined?

When a function parameter is defined, it is accessible exclusively within the function itself. This means that the scope of the parameter is limited to the function where it is defined, allowing it to be used for computations or logic within that function. Once the function execution is completed, the parameter is no longer accessible, and its value is not retained beyond the function's local environment.

This behavior is a key aspect of how local variables and parameters operate in Python, adhering to the principle of encapsulation in programming. It ensures that functions can operate independently without interfering with other parts of the program or with global variables, thereby promoting clean and maintainable code design.

The other options refer to broader scopes that do not apply to function parameters. Global scope refers to variables defined outside of functions that can be accessed from any part of the program, which is not the case for parameters. Similarly, scope in modules or in imported modules involves different rules where variables and functions defined at the module level can be accessed more broadly; however, function parameters do not fit into these categories.