#include<bits/stdc++.h>
using namespace std;
#define endl "\n"
#define debug(x) cout<<#x<<": "<<x<<endl
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
using ll=long long;
using ull=unsigned long long;
void solve(){
    int n,m,k;
    cin>>n>>m>>k;
    vector<int>e[n+1];
    for(int i = 1;i <= n;i++)
        e[i].push_back(0);
    for(int i = 1;i <= n * m;i++)
    {
        int x;
        cin>>x;
        e[(x-1)/m].push_back(i);
    }
    k = min(m,k);
    int ans = n*m;
    for(int i = 1;i <= n;i++)
        ans = min(ans,max(m,e[i][m - k]));
    ans = max(ans,m);
    cout<<ans<<endl;
}
signed main(){
    ios::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);
    int t;
    cin>>t;
    while(t--){
        solve();
    }
}
/*
贡献法
正难则反
数小状压
关系连边
拆位
广义单调性
最长转最短
*/