What is the output of the following implementation of Kadane's algorithm?

#include<stdio.h>
int max_num(int a, int b)
{  
      if(a > b)
         return a;
      return b;
}
int kadane_algo(int *arr, int len)	
{
      int ans, sum, idx;
      ans =0;
      sum =0;
      for(idx =0; idx < len; idx++)
      {
	  sum = max_num(0,sum + arr[idx]);
	  ans = max_num(sum,ans);
      }
      return ans;
}
int main()
{
      int arr[] = {-2, -3, -3, -1, -2, -1, -5, -3},len = 8;
      int ans = kadane_algo(arr,len);
      printf("%d",ans);
      return 0;
}

A. 1

B. -1

C. -2

D. 0

Answer: Option D