#include <iostream>
#include <bits/stdc++.h>
using namespace std;

int main() {
    int t;
    cin>>t;
    while(t--) {
        string s;
        int n,k;
        int count=0;
        cin>>n>>k;
        cin>>s;


        for(int i=0;i<(n/2);i++) {
            if(s[i]!=s[n-i-1]) {
                s[i]=s[n-i-1];
                count++;
            }

        }


      if(count=k) {
          cout<<"Yes"<<endl;
      }
      else {
          cout<<"No"<<endl;
      }

    }
    return 0;
}