#include<bits/stdc++.h>
#define lc(x) (x<<1)
#define rc(x) (lc(x)|1)
#define mid ((l+r)>>1)
using namespace std;
typedef long long ll;
typedef array<int,2> pr;
const int N = 2e5+10,INF = 2e9;
template<typename T>void tomin(T& x,T y){x = min(x,y);}
template<typename T>void tomax(T& x,T y){x = max(x,y);}
//
int T,n,m,k,w;
pr a[N]; int tot,ans,res;
int dp[N],b[N],cur,pre[N];

const pr Z = {INF,INF};
struct Seg{
    pr t[N<<2];
    void pu(int x){t[x] = min(t[lc(x)],t[rc(x)]);}
    void build(int x,int l,int r){
        t[x] =  Z;
        if(l==r)return;
        build(lc(x),l,mid); build(rc(x),mid+1,r);
    }
    void mdf(int x,int l,int r,int p,pr v){
        if(l==r)return tomin(t[x],v);
        (p<=mid) ? mdf(lc(x),l,mid,p,v) : mdf(rc(x),mid+1,r,p,v);
        pu(x);
    }
    pr qry(int x,int l,int r,int ql,int qr){
        if(ql>qr)return Z; if(ql<=l && qr>=r)return t[x];
        pr res = Z;
        if(ql<=mid)tomin(res,qry(lc(x),l,mid,ql,qr));
        if(qr>mid)tomin(res,qry(rc(x),mid+1,r,ql,qr));
        return res;
    }
}seg;

int qry(int x){return lower_bound(b+1,b+1+cur,x)-b;}
int rqry(int x){return upper_bound(b+1,b+1+cur,x)-b-1;}

vector<int> rev;

void cov(int L,int R){
    int x = L;
    while(x<=R){
        rev.push_back(x);
        x += k;
    }
}

void solve(){
    cin>>n>>m>>k>>w; ans = 0; rev.clear();
    tot = 0; a[++tot] = {0,0}; a[++tot] = {w+1,0};
    for(int i=1,x;i<=n;i++)cin>>x,a[++tot] = {x,1};
    for(int i=1,x;i<=m;i++)cin>>x,a[++tot] = {x,0};
    sort(a+1,a+1+tot);
    //
    for(int l=1,r;l<tot;l=r){
        r = l+1; while(r<=tot && a[r][1])r++;
        if(l==r-1)continue; 
        //
        cur = 0;
        for(int i=l+1;i<r;i++)b[++cur] = a[i][0]%k; sort(b+1,b+1+cur); cur = unique(b+1,b+1+cur)-b-1;
        seg.build(1,1,cur);

        dp[l] = 0;
        for(int i=l+1;i<r;i++){
            if(dp[i-1] != INF){
                seg.mdf(1,1,cur,qry(a[i][0]%k),(pr){dp[i-1]-a[i][0]/k,i});
            }
            dp[i] = INF; int dis = a[i+1][0] - a[i][0]; pr tmp = Z;
            //(a[i][0],k)的部分
            pr val = seg.qry(1,1,cur,qry(a[i][0]%k+1),rqry(min(k-1,a[i][0]%k+dis)));
            if(val[0] != INF){
                val[0] += a[i][0] / k;
                tomin(tmp,val);
            }
            //[0,a[i][0]]的部分
            dis -= k - a[i][0]%k;
            val = seg.qry(1,1,cur,1,rqry(min(a[i][0]%k,dis)));
            if(val[0] != INF){
                val[0] += a[i][0] / k + 1;
                tomin(tmp,val);
            }
            //
            if(tmp[0] != INF){
                dp[i] = tmp[0];
                pre[i] = tmp[1];
            }
        }
        if(dp[r-1] == INF){
            cout<<"-1\n";
            return;
        }
        ans += dp[r-1];
        for(int j=r-1;j>l;j=pre[j]-1){
            cov(a[pre[j]][0],a[j][0]);
        }
    }
    cout<<ans<<"\n";
    sort(rev.begin(),rev.end()); for(auto u : rev)cout<<u<<" "; cout<<"\n";
}
int main(){
    ios::sync_with_stdio(false); cin.tie(0);

    cin>>T;
    while(T--)solve();

    return 0;
}