#include<bits/stdc++.h>
#define ll long long
#define il inline
#define pn putchar('\n')
#define maxint 2147483647
#define min(x,y) (x<y?x:y)
#define max(x,y) (x>y?x:y)
#define maxn 100005
using namespace std;
struct Gragh
{
    int v,nex;
}e[maxn<<1];
int n,m,k,Q,top;
int c[maxn],dis[maxn],diss[maxn],f[maxn];
queue<pair<int,pair<int,int>>>q;
il void build_gra(int u,int v)
{
    e[++top]=(Gragh){v,c[u]},c[u]=top;
}
signed main()
{
    #ifndef ONLINE_JUDGE
    freopen("in.txt","r",stdin);
    #endif
    scanf("%d%d%d%d",&n,&m,&k,&Q);
    memset(dis,-1,sizeof dis);
    memset(diss,-1,sizeof diss);
    for(int i=1;i<=k;i++)
    {
        int x;
        scanf("%d",&x);
        if(dis[x]==-1)
            dis[x]=0,f[x]=i;
        else
            diss[x]=0;
        q.push(make_pair(x,make_pair(0,i)));
    }
    while(m--)
    {
        int u,v;
        scanf("%d%d",&u,&v);
        build_gra(u,v);
        build_gra(v,u);
    }
    while(q.size())
    {
        int u=q.front().first,w=q.front().second.first,ro=q.front().second.second;
        q.pop();
        for(int i=c[u];i;i=e[i].nex)
        {
            int v=e[i].v;
            if(dis[v]==-1)
                dis[v]=w+1,f[v]=ro,q.push(make_pair(v,make_pair(w+1,ro)));
            else if(diss[v]==-1&&f[v]!=ro)
                diss[v]=w+1,q.push(make_pair(v,make_pair(w+1,ro)));
        }
    }
    while(Q--)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        if(f[x]!=y)printf("%d\n",dis[x]);
        else printf("%d\n",diss[x]);
    }
    return 0;
}