A function prototype ... specifies the function's name and type signature, but omits the function implementation. specifies the function's implementation, but omits the function's name and type signature. creates multiple functions with different argument lists. is used as an initial example of a correct function signature. overloads an existing function to accept other argument types.

specifies the function's name and type signature, but omits the function implementation.

Explanation:

I will answer the question with the following illustration in C++:

double func(int a);

The above is a function prototype, and it contains the following:

double -> The function type

func -> The function name

int a -> The signature which in this case, is the parameter being passed to the function

Notice that the above does not include the function body or the implementation.

Hence, (a) is correct