#include<bits/stdc++.h>
using namespace std;
const int N = 1e5+5,mod=1e9+7;
inline int read(){
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){
        if(ch=='-')f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9')x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
    return x*f;
}
int T,n,m,v,cnt;
inline int ksm(int a,int b){
    int ans=1;
    while(b){
        if(b&1)ans=1ll*ans*a%mod;
        a=1ll*a*a%mod;
        b>>=1;
    }return ans;
}
struct node{
    int p,v;
    inline bool operator<(node b){
        return p<b.p;
    }
}a[N],b[N];
int main(){
    freopen("assign.in","r",stdin);
    freopen("assign.out","w",stdout);
    T=read();
    while(T--){
        n=read(),m=read(),v=read();
        for(int i = 1;i<=m;i++){
            a[i].p=read();
            a[i].v=read();
        }
        int ans;
        cnt=0;
        sort(a+1,a+m+1);
        for(int i = 1;i<=m;i++){
            if(i==1 || a[i].p!=a[i-1].p)b[++cnt]=a[i];
            else{
                if(a[i].v!=a[i-1].v){
                    printf("0\n");
                    goto fail;
                }
            }
        }
        ans = ksm(v*1ll*v%mod,b[1].p-1);
        for(int i = 2;i<=cnt;i++){
            ans=1ll*ans*(ksm(v*1ll*v%mod,b[i].p-b[i-1].p) - ksm(v,b[i].p-b[i-1].p-1)*1ll*(v-1)%mod)%mod;
        }
        ans=1ll*ans*(ksm(v*1ll*v%mod,n-b[cnt].p))%mod;
        printf("%d\n",(ans+mod)%mod);
        fail:;
    }
    return 0;
}