#include <bits/stdc++.h>
#define endl '\n'
using namespace std;
using ll = long long;
void solve()
{
    int n, m, k;
    cin >> n >> m >> k;
    vector<int> p(n * m + 10);
    vector<vector<int>> e(n + 1);
    for (int i = 1; i <= n * m; i++)
    {
        cin >> p[i];
        e[p[i] / m].push_back(i);
    }

    int ans = n * m;
    for (int i = 0; i < n; i++)
    {
        if (m - k - 1 < 0)
            ans = min(ans, m);
        else
            ans = min(ans, max(m, e[i][max(0, m - k - 1)]));
    }
    cout << ans << endl;
}

int main()
{
#ifdef x3ea
    freopen("in.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int _ = 1;
    cin >> _;
    for (; _; _--)
        solve();
    return 0;
}