#include<bits/stdc++.h>
#define N 1000020
#define MOD 1000000007
using namespace std;
int n, m, T, v, c[N], d[N], a[N]; 
long long ans;
void solve(){
	memset(a,0,sizeof(a));
	memset(d,0,sizeof(d));
	memset(c,0,sizeof(c));
	cin >> n >> m >> v;
	for(int i=1; i<=m; i++){
		cin >> c[i] >> d[i]; 
		a[c[i]]=d[i];
	}
	for(int i=2; i<=m; i++){
		if(c[i] == c[i-1] && d[i] != d[i-1]) {
			cout<<0<<endl;
			return;
		}  
	}
	ans=((n-1) * v % MOD * v % MOD+1)%MOD;
	cout<< ans << endl;
	return ;
}
int main(){
	freopen("assign.in","r",stdin);
	freopen("assign.out","w",stdout);
	cin>>T;
	while(T--){
		solve();
	}
	return 0;
}