#pragma GCC optimizeA("Ofast")
#pragma GCC optimizeA("inline")
#pragma GCC optimizeA("unroll-loops")
#include <bits/stdc++.h>
#define rep(i,j,k) for(int i=j;i<=k;i++)
#define rep2(i,j,k) for(int i=j;i>=k;i--)
#define mod 1000000007
#define DEBUG_VAR(x) { cerr << "* "#x" = " << x << endl; }
using namespace std;
template<typename T> void chkmin(T &x,T y){x=x<y?x:y;}
template<typename T> void chkmax(T &x,T y){x=x>y?x:y;}
template<typename T> void read(T &num){
    char c=getchar();T f=1;num=0;
    while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
    while(c>='0'&&c<='9'){num=(num<<3)+(num<<1)+(c^48);c=getchar();}
    num*=f;
}
template<typename T> T inc(T x,T y){return (x+y>=mod)?(x+y-mod):(x+y);}
template<typename T> T dec(T x,T y){return (x-y<0)?(x-y+mod):(x-y);}
int mul(int x,int y){return (1ll*x*y)%mod;}

const int N=35000;
int a[N+10];
vector<int>ver[N+10];

bool vis[N+10];
int dp[N+10][1<<5];
int w[N+10][1<<5];
int F[1<<6],G[1<<6];
int Num(int x,int i){
    return ((x>>(i-1))&1);
}
void dfs(int u,int fr){
    vis[u]=1;
    dp[u][0]=1;w[u][0]=0;
    dp[u][1]=1;w[u][1]=a[u];

    int cnt=1;
    for(auto x:ver[u]){
        if(vis[x])continue;
        dfs(x,u);
        if(!fr)continue;
        cnt++;
        int L=(int)ver[x].size();

        rep(i,0,(1<<cnt)-1)F[i]=G[i]=0;

        rep(i,0,(1<<(cnt-1))-1){
            rep(j,0,(1<<L)-1){
                if(!Num(i,cnt-1)){
                    F[i<<1|Num(j,L)]=inc(F[i<<1|Num(j,L)],mul(dp[u][i],dp[x][j]));
                    G[i<<1|Num(j,L)]=0;
                }else if(!Num(j,L)){
                    F[i<<1]=inc(F[i<<1],mul(dp[u][i],dp[x][j]));
                    G[i<<1]=w[u][i];
                }else{
                    if(w[u][i]+w[x][j]>0){
                        ;
                    }else{
                        F[i<<1|1]=inc(F[i<<1|1],mul(dp[u][i],dp[x][j]));
                        G[i<<1|1]=w[u][i]+max(0,w[x][j]);
                    }
                }
            }
        }

        rep(i,0,(1<<cnt)-1){
            dp[u][i]=F[i];
            w[u][i]=G[i];
        }
    }
    return;
}
int main()
{
    // freopen("1.in", "r", stdin);
    
    int T;
    read(T);
    while(T--){
        int n,x;
        read(n);read(x);
        rep(i,1,n){
            vis[i]=0;
            ver[i].clear();
        }

        rep(i,1,n){
            read(a[i]);
            a[i]-=x;
        }
        rep(i,1,n-1){
            int u,v;
            read(u);read(v);

            ver[u].push_back(v);
            ver[v].push_back(u);
        }

        int ans=1;
        rep(i,1,n){
            if(vis[i])continue;
            
            dfs(i,0);

            dp[i][0]=1;w[i][0]=0;
            dp[i][1]=1;w[i][1]=a[i];

            int cnt=1;
            for(auto x:ver[i]){
                cnt++;
                int L=(int)ver[x].size();

                rep(j,0,(1<<cnt)-1)F[j]=G[j]=0;

                rep(j,0,(1<<(cnt-1))-1){
                    rep(k,0,(1<<L)-1){
                        if(!Num(j,cnt-1)){
                            F[j<<1|Num(k,L)]=inc(F[j<<1|Num(k,L)],mul(dp[i][j],dp[x][k]));
                            G[j<<1|Num(k,L)]=0;
                        }else if(!Num(k,L)){
                            F[j<<1]=inc(F[j<<1],mul(dp[i][j],dp[x][k]));
                            G[j<<1]=w[i][j];
                        }else{
                            if(w[i][j]+w[x][k]>0){
                                ;
                            }else{
                                F[j<<1|1]=inc(F[j<<1|1],mul(dp[i][j],dp[x][k]));
                                G[j<<1|1]=w[i][j]+max(0,w[x][k]);
                            }
                        }
                    }
                }

                if(x==ver[i].back())continue;
                rep(j,0,(1<<cnt)-1){
                    dp[i][j]=F[j];
                    w[i][j]=G[j];
                }
            }

            int sum=0;
            rep(j,0,(1<<cnt)-1){
                sum=inc(sum,F[j]);
            }
            ans=mul(ans,sum);
        }
        cout<<ans<<endl;
    }
    return 0;
}