What is the output of the following naive method used to find the maximum sub-array sum?

#include<stdio.h>
int main()
{
     int arr[1000] = {-2, -5, 6, -2, 3, -1, 0,-5, 6}, len = 9;
     int cur_max, tmp_max, strt_idx, sub_arr_idx;
     cur_max = arr[0];
     for(strt_idx = 0; strt_idx < len; strt_idx++)
     {
	   tmp_max = 0;
	   for(sub_arr_idx = strt_idx; sub_arr_idx < len; sub_arr_idx++)
	   {
	        tmp_max += arr[sub_arr_idx];
	        if(tmp_max > cur_max)
	        cur_max = tmp_max;
	   }
     }
     printf("%d",cur_max);
     return 0;
}

A. 6

B. 9

C. 7

D. 4

Answer: Option C