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

[answerhappygod]

#include<stdio.h>
int recursive_binary_search(int *arr, int num, int lo, int hi)
{
if(lo > hi)
return -1;
int mid = (lo + hi)/2;
if(arr[mid] == num)
return mid;
else if(arr[mid] < num)
lo = mid + 1;
else
hi = mid - 1;
return recursive_binary_search(arr, num, lo, hi);
}
int main()
{
int arr[5] = {1,2,3,4,5},num = 1,len = 5;
int indx = recursive_binary_search(arr,num,0,len-1);
printf("Index of %d is %d",num,indx);
return 0;
}
a) 0
b) 1
c) 2
d) 3