What will be the output of the following C code?

#include <stdio.h>
int main()
{
    int a[4] = {1, 2, 3, 4};
    void *p = &a[1];
    void *ptr = &a[2];
    int n = 1;
    n = ptr - p;
    printf("%d\n", n);
}

A. 1

B. 4

C. Compile time error

D. Depends on the compiler

Answer: Option B