#include <bits/stdc++.h>
#define sz(x) ((int)(x).size())
#define all(x) begin(x), end(x)
#ifdef memset0
#define log(...) fprintf(stderr, __VA_ARGS__)
#else
#define endl '\n'
#define log(...) (void(0))
#endif
using namespace std;
using ll = long long;
using lf = long double;
using ull = unsigned long long;
const int N = 35010, M = 5;
const int INF = 1e9;
const int mod = 1e9 + 7;
int T, n, u, v, a[N];
int f[N][(1 << M) + 10], g[N], t[N][2], sz[N];
int lb[(1 << M) + 10], ans;
int mx[(1 << M) + 10];
ll sum[(1 << M) + 10];
vector<int> e[N], s[N];
int Check(int x, int y, int z) { return a[x] + a[y] + a[z] <= 0; }
void Merge(int x, int y) {
  // log("Merge %d %d\n", x, y);
  t[y][0] = t[y][1] = 0;
  sum[0] = a[y] + a[x];
  for (int i = 0; i < (1 << sz[y]); ++i) {
    if (i) {
      sum[i] = sum[i - (1 << lb[i])] + max(0, a[s[y][lb[i]]]);
    }
    (t[y][0] += f[y][i]) >= mod ? t[y][0] -= mod : 0;
    if (sum[i] <= 0) (t[y][1] += f[y][i]) >= mod ? t[y][1] -= mod : 0;
  }
  // log("CHK %d %d=%d\n", x, y, Check(x, y, 0));
  // log("T %d 0=%d,1=%d\n", y, t[y][0], t[y][1]);
}
void dfs(int x, int fa) {
  // log("DFS %d\n", x);
  sz[x] = 0;
  for (int i : e[x])
    if (i != fa) {
      ++sz[x];
      s[x].push_back(i);
      dfs(i, x);
      Merge(x, i);
    }
  assert(0 <= sz[x] && sz[x] <= 5);
  // log("SOLVE %d\n", x);
  g[x] = 1;
  for (int i : s[x]) {
    g[x] = 1ll * g[x] * (g[i] + t[i][0]) % mod;
  }
  sum[0] = a[x];
  mx[0] = -INF;
  for (int i = 0; i < (1 << sz[x]); ++i) {
    if (i) {
      sum[i] = sum[i - (1 << lb[i])] + max(0, a[s[x][lb[i]]]);
      mx[i] = max(mx[i - (1 << lb[i])], a[s[x][lb[i]]]);
    }
    // log("TG %d=%d\n", i, tg[i]);
    f[x][i] = (sum[i] + (mx[i] <= 0 ? mx[i] : 0) <= 0);
    for (int j = 0; j < sz[x] && f[x][i]; ++j) {
      if (i & (1 << j)) {
        f[x][i] = 1ll * f[x][i] * t[s[x][j]][1] % mod;
      } else {
        f[x][i] = 1ll * f[x][i] * g[s[x][j]] % mod;
      }
    }
  }
  // for (int i = 0; i < (1 << sz[x]); ++i) {
  //   log("F %d %d=%d\n", x, i, f[x][i]);
  // }
  // log("G %d=%d\n", x, g[x]);
}
#define clear(a) memset(a, 0, sizeof(a))
int main() {
#ifdef memset0
  freopen("F.in", "r", stdin);
  // freopen("F0.txt", "r", stdin);
#endif
  cin.tie(0)->sync_with_stdio(0);
  cin >> T;
  for (int i = 1; i < (1 << M); ++i) lb[i] = ((i & 1) ? 0 : lb[i >> 1] + 1);
  // for (int i = 1; i < (1 << M); i++) lb("lb[%d] = %d\n", i, lb[i]);
  while (T--) {
    clear(a);
    clear(f);
    clear(g);
    clear(t);
    clear(sz);
    // log("-------------------T=%d\n", T);
    cin >> n >> v;
    for (int i = 1; i <= n; ++i) cin >> a[i], a[i] -= v;
    for (int i = 1; i <= n; ++i) {
      vector<int>().swap(e[i]);
      vector<int>().swap(s[i]);
    }
    for (int i = 1; i < n; ++i) {
      cin >> u >> v;
      e[u].push_back(v), e[v].push_back(u);
    }
    dfs(1, 0);
    ll ans = g[1];
    for (int i = 0; i < (1 << sz[1]); ++i) {
      ans += f[1][i];
    }
    cout << (ans % mod) << endl;
  }
}