#include<bits/stdc++.h>
#define N 200005
#define mod 1000000007
#define gc getchar()
using namespace std;
int read(){
	int x=0;
	char ch;
	while((ch=gc)<48);
	while(ch>=48) x=x*10+ch-48,ch=gc;
	return x;
}
int power(int x,int y){
	int res=1;
	while(y){
		if(y&1) res=1ll*res*x%mod;
		x=1ll*x*x%mod;
		y=y/2;
	}
	return res;
}
int n,V,m;
struct node{
	int c,d;
}p[N];
bool cmp(node p1,node p2){
	if(p1.c==p2.c) return p1.d<p2.d;
	return p1.c<p2.c;
}
void solve(){
	n=read();m=read();V=read();
	for(int i=1;i<=m;i++) p[i].c=read(),p[i].d=read();
	sort(p+1,p+m+1,cmp);
	for(int i=2;i<=m;i++){
		if(p[i-1].c==p[i].c&&p[i-1].d!=p[i].d){
			printf("0\n");
			return;
		}
	}
	int ans=power(V,p[1].c-1+n-p[m].c);
	ans=1ll*ans*ans%mod; 
	for(int i=2;i<=m;i++){
		if(p[i].c==p[i-1].c) continue;
		int d=p[i].c-p[i-1].c;
		int w=power(V,d-1),ww=1ll*w*V%mod;
		ans=(1ll*ww*(ww-1)+w+mod)%mod*ans%mod;
	}
	printf("%d\n",ans);
}
int main(){
	freopen("assign.in","r",stdin);
	freopen("assign.out","w",stdout);
	int t=read();
	while(t--) solve();
}