#include<bits/stdc++.h>
using namespace std;
char buf[1<<20];
char *p1,*p2;
#define quick_getchar()	((p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<20,stdin))==buf)?' ':*p1++)
int read(){
	int tmp=0;
	char ch=quick_getchar();
	while(ch<'0'||ch>'9')	ch=quick_getchar();
	while(ch>='0'&&ch<='9'){(tmp*=10)+=(ch&15);ch=quick_getchar();}
	return tmp;
}
const int mod=1e9+7;
int quick(int x,int y){
	int ans=1;
	while(y){
		if(y&1)	ans=1ll*ans*x%mod;
		x=1ll*x*x%mod;
		y>>=1;
	}
	return ans;
}
int n,m,V;
struct node{int id,val;};
bool cmp(node x,node y){return x.id<y.id;}
struct node a[100005];
void work(){
	n=read();m=read();V=read();
	for(int i=1;i<=m;i++){a[i].id=read();a[i].val=read();}
	sort(a+1,a+m+1,cmp);
	for(int i=2;i<=m;i++)	if(a[i].id==a[i-1].id&&a[i].val!=a[i-1].val){printf("0\n");return;}
	int ans=quick(1ll*V*V%mod,a[1].id-1);
	for(int i=2;i<=m;i++){
		if(a[i].id==a[i-1].id)	continue;
		ans=1ll*(quick(1ll*V*V%mod,a[i].id-a[i-1].id)-1ll*quick(V,a[i].id-a[i-1].id-1)*(V-1)%mod)%mod*ans%mod;
	}
	ans=1ll*ans*quick(1ll*V*V%mod,n-a[m].id)%mod;
	printf("%d\n",(ans+mod)%mod);
}
int main(){
	freopen("assign.in","r",stdin);
	freopen("assign.out","w",stdout);
	int T=read();
	while(T--)	work();
	return 0;
}