#include <bits/stdc++.h>

using namespace std;

using pii = pair<int, int>;
using ll = long long;
const int N = 2000010, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];

ll k;
int a[N], b[N], c[N], d[N];
void solve() {
    scanf("%d%lld", &n, &k);
    for (int i = 1; i < n + 1; i++) scanf("%d", a + i);
    for (int i = 1; i < n + 1; i++) scanf("%d", b + i);
    for (int i = 1; i < n + 1; i++) scanf("%d", c + i);
    for (int i = 1; i < n + 1; i++) scanf("%d", d + i);
    multiset<pii> st;
    ll res = 0, sum = 0;
    for (int i = 1; i < n + 1; i++) {
        int p = d[i];
        st.insert({a[i], b[i]}), sum += b[i];
        while (d[i]) {
            if (st.size() && st.begin()->first < c[i]) {
                auto u = *st.begin();
                st.erase(st.begin());
                int t = min(d[i], u.second);
                d[i] -= t, u.second -= t, sum -= t;
                if (u.second) st.insert(u);
                res += (ll)(c[i] - u.first) * t;
            } else break;
        }
        if (p != d[i]) st.insert({c[i], p - d[i]}), sum += p - d[i];
        while (sum > k) {
            auto u = *st.rbegin();
            st.erase(st.find(u));
            int g = min(sum - k, (ll)u.second);
            u.second -= g, sum -= g;
            if (u.second) st.insert(u);
        }
    }
    printf("%lld\n", res);
}

int main() {
    int T = 1;
    cin >> T;
    while (T--) solve();
    return 0;
}