Which function is not called in the following C program?

#include <stdio.h>
void first()
{
    printf("first");
}
void second()
{
    first();
}
void third()
{
    second();
}
void main()
{
    void (*ptr)();
    ptr = third;
    ptr();
}

A. Function first

B. Function second

C. Function third

D. None of the mentioned

Answer: Option D