#pragma GCC optimize(2)
#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
typedef long long ll;
#define int ll
int a[35010];
struct Edge
{
	int to, nxt;
} e[70010];
int head[35010], ecnt = 0;
inline void addedge(int from, int to)
{
	e[ecnt].to = to;
	e[ecnt].nxt = head[from];
	head[from] = ecnt++;
}
int deg[35010], fa[35010], son[35010][4], scnt[35010];
int st[35010][16]; // 0: very safe, 1: half safe, 2: g
inline void dfs(int u)
{
	for(int i = head[u]; i != -1; i = e[i].nxt)
	{
		int v = e[i].to;
		if(v == fa[u])
			continue;
		son[u][scnt[u]++] = v, fa[v] = u;
		dfs(v);
	}
}
int dp[35010][3]; // 0: not chosen, 1: cannot choose fa, 2: can choose fa
inline void dfs2(int u)
{
	int m = scnt[u];
	for(int i = 0; i < m; i++)
		dfs2(son[u][i]);
	dp[u][0] = 1, dp[u][1] = dp[u][2] = 0;
	for(int i = 0; i < m; i++)
	{
		int v = son[u][i];
		dp[u][0] = dp[u][0] * (dp[v][0] + dp[v][1] + dp[v][2]) % mod;
	}
	for(int i = 0; i < (1 << m); i++)
	{
		if(st[u][i] == 2)
			continue;
		int res = 1;
		for(int j = 0; j < m; j++)
		{
			int v = son[u][j];
			if((i >> j) & 1)
				res = res * dp[v][2] % mod;
			else
				res = res * dp[v][0] % mod;
		}
		if(st[u][i])
			dp[u][1] = (dp[u][1] + res) % mod;
		else
			dp[u][2] = (dp[u][2] + res) % mod;
	}
}
signed main()
{
	int T;
	scanf("%lld", &T);
	while(T--)
	{
		int n, x;
		scanf("%lld %lld", &n, &x);
		for(int i = 1; i <= n; i++)
			scanf("%lld", &a[i]), a[i] -= x;
		for(int i = 1; i <= n; i++)
			head[i] = -1, deg[i] = 0, scnt[i] = 0;
		ecnt = 0;
		for(int i = 1; i < n; i++)
		{
			int u, v;
			scanf("%lld %lld", &u, &v);
			addedge(u, v), addedge(v, u);
			deg[u]++, deg[v]++;
		}
		int rt = 1;
		for(int i = 1; i <= n; i++)
			if(deg[i] < deg[rt])
				rt = i;
		fa[rt] = rt;
		dfs(rt);
		for(int i = 1; i <= n; i++)
		{
			int m = scnt[i];
			for(int j = 0; j < (1 << m); j++)
			{
				int sum = a[i];
				for(int k = 0; k < m; k++)
					if((j >> k) & 1)
						sum += a[son[i][k]];
				if(sum > 0 && j)
					st[i][j] = 2;
				else if(i != rt && sum + a[fa[i]] > 0)
					st[i][j] = 1;
				else
					st[i][j] = 0;
			}
			for(int j = 0; j < (1 << m); j++)
				for(int k = 0; k < (1 << m); k++)
					if((j & k) == j)
						st[i][k] = max(st[i][k], st[i][j]);
		}
		dfs2(rt);
		int ans = (dp[rt][0] + dp[rt][1] + dp[rt][2]) % mod;
		printf("%lld\n", ans);
	}
	return 0;
}