What is the expected outcome if a function does not have a return statement?

When a function does not include a return statement, the expected outcome is that it returns 'None' by default. In many programming languages, including Python, when a function finishes executing, it implicitly returns a special value that signifies 'no value' or 'no result'. This is represented by 'None' in Python.

The absence of a return statement means that the function completes its operations and exits without sending back a specific value. Therefore, when the function is called, the result of that call will be 'None', which indicates that the function has executed but hasn't provided any explicit output.

This behavior is consistent with how functions are designed to operate when they do not need to return a specific result, allowing for versatility in their use—whether for performing actions or computations that don’t necessarily require a return value.

As for the other options, they suggest scenarios that are not accurate regarding function behavior in programming. Functions can indeed be executed without return statements, they do not run indefinitely unless specifically designed to do so (like an infinite loop), and they do not trigger an error simply due to a lack of a return statement.