#include <bits/stdc++.h>
#define IOS ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define endl '\n'
#define PII pair<int, int>
#define int long long
// #define int __int128
using namespace std;
inline int read();
inline void write(int x);
const int N = 2e5 + 10, mod = 998244353, inf = 2e18, base = 131;

int a[N], b[N];

void solves()
{
    int n, m, k, w;
    cin >> n >> m >> k >> w;
    for (int i = 1; i <= n; i++)
        cin >> a[i];

    b[0] = 0, b[m + 1] = w + 1;
    for (int i = 1; i <= m; i++)
        cin >> b[i];

    sort(a + 1, a + 1 + n), sort(b + 1, b + 1 + m);

    int pos = 1;
    int ans = 0;
    vector<PII> res;
    for (int i = 1; i <= m + 1; i++)
    {
        int l = b[i - 1] + 1, r = b[i] - 1;

        if (l > r)
            continue;

        vector<int> t;
        while (pos <= n && a[pos] <= r)
        {
            t.push_back(a[pos]);
            pos++;
        }

        // cout << "***" << endl;
        // cout << "l r :" << l << ' ' << r << endl;
        // for (auto item : t)
        //     cout << item << ' ';
        // cout << endl;

        bool label = false;
        vector<PII> sc;
        for (int j = 0; j < t.size(); j++)
        {
            if (!sc.size())
            {
                int L = t[j], R = t[j] + k - 1;
                if (R <= r)
                {
                    sc.push_back({L, R});
                }
                else
                {
                    label = true;
                    break;
                }
            }
            else
            {
                int bl = sc.back().first, br = sc.back().second;
                if (t[j] >= bl && t[j] <= br)
                    continue;
                int L = t[j], R = t[j] + k - 1;
                if (R <= r)
                {
                    sc.push_back({L, R});
                }
                else
                {
                    label = true;
                    break;
                }
            }
        }

        // cout<<"SC: "<<endl;
        // cout<<label<<endl;
        // for(auto item:sc) cout<<item.first<<' '<<item.second<<endl;

        if (label)
        {
            if (sc.size() == 0)
            {
                int R = r;
                int L = r - k + 1;
                if (L < l)
                {
                    cout << -1 << endl;
                    return;
                }
            }
            else
            {
                vector<PII> sb;
                int R = r;
                int L = r - k + 1;
                while (1)
                {
                    int ll = sc.back().first, rr = sc.back().second;
                    if (rr <= R && rr >= L)
                    {
                        sc.pop_back();
                        sb.push_back({L, R});
                        R = L - 1, L = R - k + 1;
                    }
                    else
                    {
                        sb.push_back({L, R});
                        ans += sc.size() + sb.size();
                        for (auto item : sc)
                            res.push_back(item);
                        for (auto item : sb)
                            res.push_back(item);
                        break;
                    }

                    if (sc.size() == 0)
                    {
                        if (L < l)
                        {
                            cout << -1 << endl;
                            return;
                        }
                        else
                        {
                            sb.push_back({L, R});
                            ans += sb.size();
                            for (auto item : sb)
                                res.push_back(item);
                            break;
                        }
                    }
                }
            }
        }
        else
        {
            for (auto item : sc)
                res.push_back(item);
            ans += sc.size();
        }
    }

    // cout<<"***********"<<endl;

    cout << ans << endl;

    for (auto item : res)
        cout << item.first << ' ';
    cout << endl;
}

signed main()
{
    IOS;
    int t = 1;
    cin >> t;
    while (t--)
        solves();
}