What is the space complexity of the following dynamic programming implementation of the matrix chain problem?

#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] = {20,5,30,10,40};
     int ans = mat_chain_multiplication(mat,5);
     printf("%d",ans);
     return 0;
}

A. O(1)

B. O(n)

C. O(n²)

D. O(n³)

Answer: Option C