What is the output of the following code?

#include<stdio.h>
#include<limits.h>
int mat_chain_multiplication(int *mat, int n)
{
     int arr[n][n];
     int i,k,row,col,len;
     for(i=1;i<n;i++)
         arr[i][i] = 0;
     for(len = 2; len < n; len++)
     {
          for(row = 1; row <= n - len + 1; row++)
          {
               col = row + len - 1;
               arr[row][col] = INT_MAX;
               for(k = row; k <= col - 1; k++)
               {
                    int tmp = arr[row][k] + arr[k + 1][col] + mat[row - 1] * mat[k] * mat[col];
                    if(tmp < arr[row][col])
                    arr[row][col] = tmp;
               }
           }
     }
     return arr[1][n - 1];
}
int main()
{
     int mat[6] = {20,30,40,50};
     int ans = mat_chain_multiplication(mat,4);
     printf("%d",ans);
     return 0;
}

A. 64000

B. 70000

C. 120000

D. 150000

Answer: Option A