What will be the output of the following C code?

#include <stdio.h>
int add(int a, int b)
{
    return a + b;
}
int main()
{
    int (*fn_ptr)(int, int);
    fn_ptr = add;
    printf("The sum of two numbers is: %d", (int)fn_ptr(2, 3));
}

A. Compile time error, declaration of a function inside main

B. Compile time error, no definition of function fn_ptr

C. Compile time error, illegal application of statement fn_ptr = add

D. No Run time error, output is 5

Answer: Option D