#include<cstdio>
#include<map>
#include<iostream>
using namespace std;
typedef long long ll;
inline ll read(){
	ll x=0;
	int f=0,ch=0;
	while(ch<48||ch>57) f=(ch=='-'),ch=getchar();
	while(ch>47&&ch<58) x=(x<<3)+(x<<1)+(ch&15),ch=getchar();
	return f?-x:x;
}
inline void write(ll x,char end=' '){
	if(x==0){
		putchar('0');
		putchar(end);
		return;
	}
	if(x<0) putchar('-'),x=-x;
	int ch[40]={0},cnt=0;
	while(x){
		ch[cnt++]=(int)(x%10);
		x/=10;
	}
	while(cnt--) putchar(ch[cnt]+48);
	putchar(end);
}
const int N=1e5+5;
const ll mod=1e13+7;
int n,m;
string s;
int fa[N];
map<ll,int> mp;
ll base[N];
inline ll hsh(){
	ll h=0;
	for(int i=0;i<m;++i)
		h=(h*37%mod+s[i]-'a'+1)%mod;
	return h;
}
int main(){
	base[0]=1;
	for(int i=1;i<N;++i) base[i]=base[i-1]*37%mod;
	int T=read();
	while(T--){
		n=read(),m=read();
		mp.clear();
		for(int i=1;i<=n;++i) fa[i]=i;
		for(int i=1;i<=n;++i){
			cin>>s;
			ll t=hsh();
//			printf("%lld ",t);
			if(mp[t])
				fa[i]=fa[mp[t]];
			else{
				mp[t]=fa[i];
				for(int j=0;j<m-1;++j){
					int c=s[j]-'a'+1;
					t=(t-c*base[m-1]%mod)%mod;
					t=(t+mod)%mod;
					t=(t*37%mod+c)%mod;
//					printf("%lld ",t);
					mp[t]=fa[i];
				}
			}
//			puts("");
		}
		int q=read();
		while(q--){
			int x=read(),y=read();
			if(fa[x]==fa[y]) puts("Yes");
			else puts("No");
		}
	}
	return 0;
}