#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1e5+10;
int n,m,q,V;
vector<int> g[N];
vector<int> e[N];
void add(int x,int y,int w=1)
{
    g[x].push_back(y);
    e[x].push_back(w);
}
int vis[N];
int dfs(int x,int y,int s=0,int step=1)
{
    if(x==y) return s;
    else if(g[x].size()==0) return 0;
    else{
        vis[x]=1;
        int ans=0;
        for(int i=0;i<g[x].size();i++)
        {
            int v=g[x][i],w=e[x][i],t=s;
            if(vis[v]) continue;
            if(step==1) s=w;
            else s&=w;
            vis[v]=1;
            ans=max(ans,dfs(v,y,s,step+1));
            vis[v]=0;
            s=t;
        }
        return ans;
    }
}
int main()
{
    freopen("Paths.in","r",stdin);
    freopen("Paths.out","w",stdout);
    
    cin>>n>>m>>q>>V;
    if(n>100){
        printf("I can't do it.");
        return 0;
    }
    for(int i=1;i<=m;i++)
    {
        int x,y,w;
        cin>>x>>y>>w;
        add(x,y,w),add(y,x,w);
    }
    for(int i=1;i<=q;i++)
    {
        int x,y;
        cin>>x>>y;
        memset(vis,0,sizeof(vis));
        int t=dfs(x,y);
        cout<<t<<endl;
        if(t>=V) cout<<"Yes"<<endl;
        else cout<<"No"<<endl;
    }
    return 0;
}