//Nguyen Huu Hoang Minh
#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define reset(x) memset(x, 0,sizeof(x))
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define N 200005
#define remain(x) if (x > MOD) x -= MOD
#define ii pair<int, int>
#define iiii pair< ii , ii >
#define viiii vector< iiii >
#define vi vector<int>
#define vii vector< ii >
#define bit(x, i) (((x) >> (i)) & 1)
#define Task "test"

using namespace std;

typedef long double ld;

int t, n, m, k, q;

void readfile()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    if (fopen(Task".inp","r"))
    {
        freopen(Task".inp","r",stdin);
        //freopen(Task".out","w",stdout);
    }
    cin >> t;
}

int Pow(int a, int mu, int mod){
    if (mu==1) return a;
    int tmp = Pow(a,mu/2,mod);
    if (mu%2==0) return tmp*tmp%mod;
    return tmp*tmp%mod*a%mod;
}

void solve(){
    cin >> n >> m >> k >> q;
    vii color(q);
    for(int i=0; i<q; i++){
        cin >> color[i].fi >> color[i].se;
        color[i].fi--; color[i].se--;
    }
    int tplt = 0;
    int ir = 0, ic = 0;
    vector<bool> xc(n,0), yc(m,0);
    for(int i=q-1; i>0; i--){
        int cr = color[i].fi, cc = color[i].se;
        if (xc[cr] && yc[cc]) continue;
        while (ir < n && xc[ir]) ir++;
        while (ic < m && yc[ic]) ic++;
        if (ir==n || ic==m) continue;
        xc[cr]=1; yc[cc] = 1;
        tplt++;
    }
    const int mod = 998244353;
    cout << Pow(k,tplt,mod) << '\n';
}

void proc()
{
    while (t--){
        solve();
    }
}

signed main()
{
    readfile();
    proc();
    return 0;
}