#include<bits/stdc++.h>
using namespace std;
#define ll long long 
#define pii pair<int, int>

#define db(args...){\
    string _s = #args; replace(_s.begin(), _s.end(), ',', ' ');\
    stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); cout << '\n';}
void err(istream_iterator<string> it){}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
    cout << *it << " = " << a << ' ';
    err(++it, args...);
}

void solve() {
    ll n, m, k, w;
    cin >> n >> m >> k >> w;

    vector<int> a(n), b(m);
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < m; i++) cin >> b[i];
    b.push_back(0); b.push_back(w + 1);
    sort(a.begin(), a.end());
    sort(b.begin(), b.end());

    bool ok = 1;
    vector<int> ans;

    auto wk = [&] (vector<int> a, int L, int R) {

        a.insert(a.begin(), L);
        int n = a.size();
        if (n == 1) return;

        vector<int> pre(n, -1), pos(n);
        pos[0] = L;
        for (int i = 1, j = 0; i < n; i++) {
            if (i == 1) {
                int l = max((ll)L, a[i] - k + 1);
                int r = l + k - 1;
                if (i + 1 < n && r > a[i + 1]) continue;
                if (i == n - 1 && r > R) continue;
                pre[i] = 0;
                pos[i] = r;
                continue;
            }

            while (a[i] - a[j] + 1 > k) {
                j++;
            }
            assert(j == 0 || pos[j - 1] < a[j]);
            int l = max(pos[j - 1] + 1ll, a[i] - k + 1);
            int r = l + k - 1;
            if (i + 1 < n && r >= a[i + 1]) continue;
            if (i == n - 1 && r > R) continue;
            pos[i] = l + k - 1;
            pre[i] = j - 1;
        }
        
        if (pre[n - 1] == -1) {
            ok = 0;
        } else {
            int x = n - 1;
            while (pre[x] != -1) {
                ans.push_back(pos[x]);
                x = pre[x];
            }
        }
    };
    for (int i = 1; i < b.size(); i++) {
        int x = b[i - 1], y = b[i];
        auto p = lower_bound(a.begin(), a.end(), x);
        auto q = lower_bound(a.begin(), a.end(), y);
        wk(vector<int>(p, q), x + 1, y - 1);
        if (!ok) break;
    }
    if (!ok) {
        cout << "-1\n";
        return;
    }
    cout << ans.size() << '\n';
    
    for (int i = 0; i < ans.size(); i++) {
        cout << ans[i] - k + 1 << " \n" [i + 1 == ans.size()];
    }
}  
signed main() {
    ios::sync_with_stdio(0); cin.tie(0);

    int t = 1;
    cin >> t;
    while (t--) solve();
    return 0;
}

/*
g++ 1.cpp -std=c++20 -o 1 && ./1 < in.txt > out.txt
 */



// L
// void pre(int n) {
//     vector<int> p(n);
//     iota(p.begin(), p.end(), 0);
//     db(n);
//     do {
//         set<int> st;
//         for (int i = 0; i < n; i++) {
//             st.insert(p[i] ^ i);
//         }
//         if (st.size() == n) {
//             for (auto x : p) cout << x << ' ';
//             cout << '\n';
//             return;
//         } 
//     } while (next_permutation(p.begin(), p.end())); 
//     cout << "No\n";
// }