What is the output of the following code?

#include<stdio.h>
#include<string.h>
int get_min(int a, int b)
{
     if(a < b)
         return a;
     return b;
}
int edit_distance(char *s1, char *s2)
{
     int len1,len2,i,j,min;
     len1 = strlen(s1);
     len2 = strlen(s2);
     int arr[len1 + 1][len2 + 1];
     for(i = 0;i <= len1; i++)
       arr[i][0] = i;
     for(i = 0; i <= len2; i++)
       arr[0][i] = i;
     for(i = 1; i <= len1; i++)
     {
         for(j = 1; j <= len2; j++)
         {
              min = get_min(arr[i-1][j],arr[i][j-1]) + 1;
              if(s1[i - 1] == s2[j - 1])
              {
                  if(arr[i-1][j-1] < min)
                     min = arr[i-1][j-1];
              }
              else
              {
                  if(arr[i-1][j-1] + 1 < min)
                      min = arr[i-1][j-1] + 1;
              }
              arr[i][j] = min;
         }
     }
     return arr[len1][len2];
}
int main()
{
     char s1[] = "abcd", s2[] = "dcba";
     int ans = edit_distance(s1, s2);
     printf("%d",ans);
     return 0;
}

A. 1

B. 2

C. 3

D. 4

Answer: Option D