#include<bits/stdc++.h>
using namespace std;
int n,m;
const int mod=1e9+7;
vector<int>g[201000];
#define pi pair<int,int>
#define fi first
#define se second
#define pb push_back
vector<pi>e[200100];
int vis[201000],z[200100];
void dfs(int x,int f){
    vector<pi>ex;
    ex.clear();ex.pb({1,1});
    for(int v:g[x])if(v!=f){
        dfs(v,x);vector<int>P;
        for(pi a:ex)for(pi b:e[v]){
            int h=a.fi+b.fi;
            if(h>m+1)continue;
            if(!vis[h])vis[h]=1,P.pb(h);
            (z[h]+=1ll*a.se*b.se%mod)%=mod;
        }
        ex.clear();
        for(int i:P)vis[i]=0,ex.pb({i,z[i]}),z[i]=0;
    }
    int t0=0;
    for(pi o:ex)if(o.fi==m||o.fi==m+1)(t0+=o.se)%=mod;
    if(t0){
        bool fl=0;
        for(pi &o:ex)if(!o.fi){fl=1,(o.se+=t0)%=mod;break;}
        if(!fl)ex.pb({0,t0});
    }
    e[x]=ex;
}
void sol(){
    scanf("%d%d",&n,&m);for(int i=1;i<=n;i++)g[i].clear();
    for(int i=1,u,v;i<n;i++)scanf("%d%d",&u,&v),g[u].pb(v),g[v].pb(u);
    dfs(1,0);
    for(pi z:e[1])if(z.fi==0){printf("%d\n",z.se);return;}
    puts("0");
}
int main(){
    int T;scanf("%d",&T);while(T--)sol();
    return 0;
}