#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 35000 + 5;
const int P = 1e9 + 7;

int N, a[MAX_N];
vector <int> edge[MAX_N];
int f[MAX_N][17], son[MAX_N][4], cnt[MAX_N];

inline int add(int a, int b) {return a < P - b ? a + b : a - P + b;}

void dfs(int u, int fa) {
    f[u][0] = 1;
    f[u][16] = 1;
    for (int i = 0; i < (int)edge[u].size(); i ++) {
        if (edge[u][i] != fa) {
            dfs(edge[u][i], u);
            son[u][cnt[u] ++] = edge[u][i];
        }
    }
    for (int i = 0; i < cnt[u]; i ++) {
        int v = son[u][i], sum = f[v][16];
        for (int s = 0; s < (1 << cnt[v]); s ++) sum = add(sum, f[v][s]);
        // fprintf(stderr, "u = %d, v = %d, sum = %d\n", u, v, sum);
        int g[17]; memset(g, 0, sizeof g);
        g[16] = 1ll * f[u][16] * sum % P;
        for (int s = 0; s < (1 << i + 1); s ++) {
            if (s >> i & 1) {
                if (a[u] + a[v] > 0) continue;
                sum = 0;
                for (int j = 0; j < cnt[u]; j ++) {
                    if (s >> j & 1) {
                        sum += max(a[son[u][j]], 0);
                    }
                }
                if (a[u] + sum > 0) continue;
                for (int t = 0; t < (1 << cnt[v]); t ++) {
                    sum = 0;
                    for (int j = 0; j < cnt[v]; j ++) {
                        if (t >> j & 1) {
                            sum += max(a[son[v][j]], 0);
                        }
                    }
                    if (sum + a[u] + a[v] <= 0) {
                        g[s] = (g[s] + 1ll * f[u][s ^ (1 << i)] * f[v][t]) % P;
                    }
                }
            }else {
                g[s] = 1ll * f[u][s] * f[v][16] % P;
            }
        }
        memcpy(f[u], g, sizeof g);
    }
    // fprintf(stderr, "u = %d\n", u);
    // for (int i = 0; i < 17; i ++) fprintf(stderr, "i = %d, f = %d\n", i, f[u][i]);
}

void solve() {
    int x;
    cin >> N >> x;
    for (int i = 1; i <= N; i ++) {
        cin >> a[i]; a[i] -= x;
        edge[i].clear();
        cnt[i] = 0;
        memset(f[i], 0, sizeof f[i]);
        memset(son[i], 0, sizeof son[i]);
    }
    for (int i = 1; i < N; i ++) {
        int x, y;
        cin >> x >> y;
        edge[x].push_back(y);
        edge[y].push_back(x);
    }
    dfs(1, 0);
    int ans = 0;
    for (int i = 0; i < 17; i ++) ans = add(ans, f[1][i]);
    cout << ans << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    
    int T;
    cin >> T;
    while (T --) solve();
    
    return 0;
}