#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int t;
  while (cin >> t) {
    while (t--) {
      long long int n;
      cin >> n;
      long long int ar[n];
      long long int odd = 0;
      long long int even = 0;
      long long int a, b;
      vector<long long int> v;
      for (long long int i = 0; i < n; i++) {
        cin >> ar[i];
      }
      long long int flag = 0;
      for (long long int i = 0; i < n; i++) {
        if (ar[i] % 2 == 0) {
          a = i + 1;
          flag = 1;
          break;
        } else
          odd++;
        if (odd % 2 == 0) {
          break;
        }
      }
      if (flag == 1) {
        cout << 1 << endl;
        cout << a << endl;
      } else {
        if (odd == 1)
          cout << -1 << endl;
        else {
          cout << 2 << endl;
          long long int c = 0;
          for (long long int i = 0; i < n; i++) {
            if (ar[i] % 2 == 1) {
              cout << i + 1 << " ";
              c++;
            }
            if (c == 2) break;
          }
        }
      }
    }
  }
}
