What is the output of the following code?

#include<stdio.h>
#include<limits.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 max_sum_rectangle(int arr[][5],int row,int col)
{
      int left, right, tmp[row], mx_sm = INT_MIN, idx, val;
      for(left = 0; left < col; left++)
      {
           for(right = left; right < col; right++)
           {
                if(right == left)
                {
                    for(idx = 0; idx < row; idx++)
                     tmp[idx] = arr[idx][right];
                }
                else
                {
                     for(idx = 0; idx < row; idx++)
                       tmp[idx] += arr[idx][right];
                }
                val = kadane_algo(tmp,row);
                if(val > mx_sm)
                mx_sm = val;
           }
      }  
      return mx_sm;
}
int main()
{
       int arr[2][5] ={{1, 2, -1, -4, -20}, {-4, -1, 1, 7, -6}};
       int row = 2, col = 5;
       int ans = max_sum_rectangle(arr,row,col);
       printf("%d",ans);
       return 0;
}

A. 7

B. 8

C. 9

D. 10

Answer: Option B