#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<stack>
#include<set>
#include<string>
#include<iostream>
#include<map>
#include<queue>
#pragma comment(linker,"/STACK:102400000,102400000") 
using namespace std;
char mp[55][55];
int n,m,sx,sy,tx,ty,dir[4][2]={1,0,-1,0,0,1,0,-1};
double dis[55][55];
struct thanks{
    int x,y,k;
    double v;
}now,temp;
queue<thanks> q;
bool ok(thanks pt){
    if(pt.x>=1 && pt.x<=n && pt.y>=1 && pt.y<=m && mp[pt.x][pt.y]!='#' && pt.k>0) return 1;
    else return 0;
}
void bfs(){
    while(!q.empty()){
        now=q.front();
        q.pop();
        for(int i=0;i<4;i++){
            temp.x=now.x+dir[i][0];
            temp.y=now.y+dir[i][1];
            temp.k=now.k-1;
            if(ok(temp)){
                temp.v=now.v+1.0*abs(mp[now.x][now.y]-mp[temp.x][temp.y])/now.k;
                if(dis[temp.x][temp.y]==-1 || temp.v<dis[temp.x][temp.y]){
                    dis[temp.x][temp.y]=temp.v;
                    q.push(temp);
                }
            }
        }
    }
}
int main(){
    int i,j,t,T,k;
    scanf("%d",&T);
    while(T--){
        scanf("%d%d%d",&n,&m,&k);
        for(i=1;i<=n;i++)
            for(j=1;j<=m;j++) dis[i][j]=-1.0;
        for(i=1;i<=n;i++){
            scanf("%s",mp[i]+1);
        }
        scanf("%d%d%d%d",&sx,&sy,&tx,&ty);
        now.x=sx,now.y=sy,now.k=k,now.v=0;
        if(now.k>0){
            dis[sx][sy]=0;
            q.push(now);
        }
        bfs();
        if(dis[tx][ty]==-1) printf("No Answer\n");
        else printf("%.2lf\n",dis[tx][ty]);
    }
    //system("pause");
    return 0;
}