/*****************************************************************
    Author:lbn187, a konjac TwT
    Date:2016-03-05
    Contest:Bestcoder
    Algorithm:QAQ
    ^_^  Orz hzh, NOI gold members, IOI 2016 world champion
    ^=^  Orz hhw, you are our blue moon, with you will live
    ^~^  Orz mxh, you are our red sun, without you we'll die
    ^-^  Orz yizhou, I wish you a successful marriage
    ^w^  Orz xianyangyu, you can sleep all the time in the game
*****************************************************************/
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<map>
#include<set>
#include<bitset>
#define fo(i,n) for(int i=0;i<n;i++)
#define fr(i,n) for(int i=1;i<=n;i++)
#define dr(i,n) for(int i=n;i;i--)
#define do(i,n) for(int i=n-1;i>=0;i--)
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,a,n) for(int i=n;i>=a;i--)
#define mjj(i,x) for(int i=fir[x];i;i=ne[i])
#define X first
#define Y second
#define MAX(a,b) a=max(a,b)
#define MIN(a,b) a=min(a,b)
#define mp make_pair
#define gi(a) scanf("%d",&a);
#define gi2(a,b) scanf("%d%d",&a,&b);
#define gi3(a,b,c) scanf("%d%d%d",&a,&b,&c);
#define gl(a) scanf("%I64d",&a);
#define gs(s) scanf("%s",s);
#define wi(a) printf("%d\n",a);
#define wi2(a,b) printf("%d %d\n",a,b);
#define wl(a) printf("%I64d\n",a);
#define spr(x) (x*x)
#define pi acos(-1) 
#define CM(a,b) memcpy(a,b,sizeof(b))
#define CL(a) memset(a,0,sizeof(a))
#define N 111111
#define M 1000000007
#define inf 1e9
#define eps 1e-8
using namespace std;

typedef long long LL;typedef unsigned long long ULL;typedef double LF;typedef long double LD;
typedef pair<int,int>pii;typedef pair<int,LL>pil;typedef pair<LL,int>pli;typedef pair<LL,LL>pll;typedef pair<LF,LF>pff;
const int xx[]={1,-1,0,0},yy[]={0,0,1,-1};LL pow(LL a,LL b,LL p){LL sum=1;for(a%=p;b;a=a*a%p,b>>=1)if(b&1)sum=sum*a%p;return sum;}
char ch;void rd(int &x){for(ch=getchar();ch<'0';ch=getchar());for(x=0;ch>='0';ch=getchar())x=x*10+ch-'0';}
LL phi(LL n){LL i,re=n;for(i=2;i*i<=n;i++)if(n%i==0){re=re/i*(i-1);while(n%i==0)n/=i;}if(n>1)re=re/n*(n-1);return re%M;}
void exgcd(LL a,LL b,LL &x,LL &y){if(!b){x=1;y=0;return;}exgcd(b,a%b,y,x);y-=x*(a/b);}
LL gcd(LL a,LL b){return b==0?a:gcd(b,a%b);}

int T,n,m,x,y,i,j,k,h,t,tot,a[N],du[N],la[N*2],ne[N*2],fir[N],mv[N*4];bool v[N];
void ins(int x,int y){
    la[++tot]=y;ne[tot]=fir[x];fir[x]=tot;du[y]++;
}
void bt(int k,int l,int r){
    if(l==r){mv[k]=du[l];return;}
    int mid=l+r>>1;bt(k<<1,l,mid);bt(k<<1|1,mid+1,r);
    mv[k]=min(mv[k<<1],mv[k<<1|1]);
}
int get(int k,int l,int r,int x){
    if(l==r){
        if(mv[k]<=x)return l;else return -1;
    } 
    int mid=l+r>>1;
    if(mv[k<<1]<=x)return get(k<<1,l,mid,x);
    if(mv[k<<1|1]<=x)return get(k<<1|1,mid+1,r,x);
    return -1;
}
void cha(int k,int l,int r,int x,int z){
    if(l==r){mv[k]=z;return;}
    int mid=l+r>>1;
    if(x<=mid)cha(k<<1,l,mid,x,z);else cha(k<<1|1,mid+1,r,x,z);
    mv[k]=min(mv[k<<1],mv[k<<1|1]);
}
int main(){
    scanf("%d",&T); 
    for(;T--;){
        CL(fir);tot=0;CL(du);CL(v);CL(mv);LL S=0;
        scanf("%d%d%d",&n,&m,&k);
        for(i=1;i<=m;i++)scanf("%d%d",&x,&y),ins(x,y);
        bt(1,1,n);
        for(i=1;i<=n;i++){
            x=get(1,1,n,k);
            S=(S+1ll*i*x)%M;
            cha(1,1,n,x,1e9);k-=du[x];v[x]=1;
            for(int j=fir[x];j;j=ne[j]){
                du[la[j]]--;
                if(!v[la[j]])cha(1,1,n,la[j],du[la[j]]);
            }
        }
        printf("%lld\n",S);
        //fr(i,n)scanf("%d",&a[i]);
    }
}