In PHP, which constant returns the name of the current function?

The constant that returns the name of the current function in PHP is FUNCTION. This constant is specifically designed to provide the function's name in which it is called, making it very useful for debugging and logging purposes. When used within a function, it returns a string with the exact name of that function, regardless of how many times it has been called or from where in the code.

Using FUNCTION helps in scenarios where one might want to implement functionality conditionally based on the function name or to log activity related to specific functions. Since PHP automatically handles the scoping and context, it ensures that the right function name is always returned as expected.

The other options do not accurately achieve this specific task. METHOD would return the name of the method in the context of an object, including the class name, making it unsuitable when only the function name is needed. The function get_function_name() does not exist in PHP's built-in functions. Similarly, current_function() is also not a recognized PHP function. Thus, FUNCTION is indeed the correct choice for retrieving the name of a function in PHP.