What is the return value of a function?

A function's return value is the output that it provides upon execution. When a function is called, it may perform calculations, process data, or perform actions, and eventually, it will return a specific value that can be used by the calling code. This value can be any data type, including numbers, strings, or even objects, depending on what the function was designed to compute or provide.

The return statement in a function indicates what value is sent back to the part of the program that called the function. This allows the caller to capture and utilize the result of the function for further processing.

In contrast, calling a function refers to the action of executing it, while the data passed to the function (usually as parameters) are inputs necessary for the function to perform its task. Lastly, a variable in the declaration of the function is simply a placeholder that can be used within the function’s code, not the result the function provides. Thus, the most accurate description of a function's return value is indeed its output.