How many times is the function recursive_sum() called when the following code is executed?

[answerhappygod]

#include<stdio.h>
int recursive_sum(int n)
{
if(n == 0)
return 0;
return n + recursive_sum(n - 1);
}
int main()
{
int n = 5;
int ans = recursive_sum(n);
printf("%d",ans);
return 0;
}
a) 4
b) 5
c) 6
d) 7