Final answer:
Without the actual PHP function's code provided, it is impossible to determine what the function will return. A PHP function needs to have a return statement to return a value, otherwise, it will return NULL by default. Providing the PHP code is necessary for a precise answer.
Step-by-step explanation:
The PHP function in question is not provided in the student's question, which is essential information needed to determine what the function will return. Without the function's code, it is impossible to accurately say whether it will return "Peter", "Griffin", "Peter Griffin", or if it will not return anything at all.
If the student can provide the PHP function's code, I would be able to analyze the function and give a definitive answer to what the function will return. Any PHP function that is supposed to return a value should include a return statement with the value that needs to be returned. If there's no return statement within the function, then by default, the function will return NULL..