#include <iostream>
#include <math.h>
#include <string>
#include <algorithm>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <sstream>
#include <map>
#include <queue>
#include <set>
#include <vector>
#include <stack>
#include <cstdio>
#include <fstream>

//#include <bits/stdc++.h>
using namespace std;
#define fastIO ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define ll  long long
#define mp make_pair
#define mod (ll)1000000007
#define inf 1e17
#define PI acos(-1)

int t;
int n, m, k;
int x[111][111];
int pre[111][111];

int ch(int i, int j, int h, int w) {
	return pre[h][w] - pre[i - 1][w] - pre[h][j - 1] + pre[i - 1][j - 1];
}
int cal(int i, int j, int h, int w){
	return (h - i + 1)*(w - j + 1);
}
int main()
{
	fastIO;
	cin >> t;
	while (t--){
		cin >> n >> m >> k;
		for (int i = 1; i <= n; i++){
			for (int j = 1; j <= m; j++){
				cin >> x[i][j];
				pre[i][j] = x[i][j] + pre[i][j - 1];
			}
		}
		for (int i = 1; i <= n; i++){
			for (int j = 1; j <= m; j++){
				pre[i][j] += pre[i - 1][j];
			}
		}
		int mx = 0;
		for (int i = 1; i <= n; i++){
			for (int j = 1; j <= m; j++){
				for (int i1 = i; i1 <= n; i1++){
					for (int j1 = j; j1 <= m; j1++){
						if (ch(i, j, i1, j1) <= k){
							int temp = cal(i, j, i1, j1);
							if (mx < temp){
								mx = temp;
							}
						}
					}
				}
			}
		}
		cout << mx << endl;
	}
	return 0;
}