#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
    int x=0;char ch;
    do ch=getchar();while(ch<'0'||ch>'9');
    do x=(x<<3)+(x<<1)+(ch^48),ch=getchar();while(ch>='0'&&ch<='9');
    return x;
}
const int N=1e5+5,mod=1e9+7;
struct ass{
    int p,v;
    bool operator<(const ass &x)const{
        return p<x.p;
    }
    bool operator==(const ass &x)const{
        return p==x.p&&v==x.v;
    }
}a[N];
int n,m,v;
int qpow(int x,int y=mod-2){
    int res=1;
    while(y){
        if(y&1)res=res*x%mod;
        x=x*x%mod;y>>=1;
    }
    return res;
}
void solve(){
    n=read();m=read();v=read();
    for(int i=1;i<=m;i++){
        int p=read(),v=read();
        a[i]={p,v};
    }
    sort(a+1,a+1+m);
    for(int i=1;i<m;i++){
        if(a[i].p==a[i+1].p&&a[i].v!=a[i+1].v){
            puts("0");return;
        }
    }
    m=unique(a+1,a+1+m)-a-1;
    if(m<=1){
        printf("%lld\n",qpow(v,2*(n-1)));
        return;
    }
    int ans=1;
    if(a[1].p!=1)ans=ans*qpow(v,2*(a[1].p-1))%mod;
    for(int i=1;i<m;i++){
        if(a[i].p+1==a[i+1].p)ans=ans*(v*v%mod+mod-v+1)%mod;
        else{
            int x=a[i].p,y=a[i+1].p;
            ans=ans*(qpow(v,2*(y-x))+mod-qpow(v,y-x-1)*(v-1)%mod)%mod;
        }
    }
    if(a[m].p!=n)ans=ans*qpow(v,2*(n-a[m].p))%mod;
    printf("%lld\n",ans);
}
signed main(){
    freopen("assign.in","r",stdin);
    freopen("assign.out","w",stdout);
    int T=read();
    while(T--)solve();
    return 0;
}