#include<bits/stdc++.h>
using namespace std;
inline int read(){
    int x(0),f(1);char c=getchar();
    while(c<'0'||c>'9')f=c=='-'?-1:1,c=getchar();
    while(c<='9'&&c>='0')x=x*10+c-48,c=getchar();
    return x*f;
}
const int mod=1e9+7;
inline int Mul(int x,int y){return 1ll*x*y%mod;}
inline int Inc(int &x,int y){return x-=(x+=y)>=mod?mod:0;}
inline int Dec(int &x,int y){return x+=(x-=y)<0?mod:0;}
inline int ksm(int a,int n){
    int ans=1;
    while(n){
        if(n&1)ans=Mul(ans,a);
        a=Mul(a,a);n>>=1;
    }
    return ans;
}
const int M=100010;
int fac[M],inv[M],pw;
void inits(int N=::M-10){
    fac[0]=1;for(int i=1;i<=N;i++)fac[i]=Mul(fac[i-1],i);
    inv[N]=ksm(fac[N],mod-2);for(int i=N-1;i>=0;i--)inv[i]=Mul(inv[i+1],i+1);
}
inline int C(int n,int m){return m<0||n<m?0:Mul(fac[n],Mul(inv[m],inv[n-m]));}
int n,m,v;
struct node{
    int p,v;
}a[M];int tot=0;
vector<int>p;
inline void solve(){
    n=read(),m=read();v=read();tot=0;
    pw=Mul((mod+1-v)%mod,ksm(v,mod-2));

    for(int i=1;i<=m;i++)a[i].p=read(),a[i].v=read();
    sort(a+1,a+m+1,[](node a,node b){return a.p<b.p;});
    for(int i=1;i<=m;i++)if(a[i].p!=a[i-1].p)a[++tot]=a[i];
    else if(a[i].v!=a[i-1].v)return puts("0"),void();
    m=tot;p.clear();for(int i=1;i<m;i++)p.push_back(a[i+1].p-a[i].p);
    
    int ans=ksm(v,2*n-2),iv=ksm(v,mod-2);
    for(auto i:p){
        int x=(Mul(ksm(iv,i),pw)+1)%mod;
        ans=Mul(ans,x);
    }

    // cerr<<ans<<endl;
    printf("%d\n",ans);
}
int main(){
    freopen("assign.in","r",stdin);
    freopen("assign.out","w",stdout);
    int T=read();inits();
    while(T--)solve();
    return 0;
}