#include <bits/stdc++.h>
using namespace std;
const long long N = 1000000;
int32_t main() {
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    long long a[n];
    long long e = 0;
    for (long long i = 0; i < n; i++) {
      cin >> a[i];
      if (a[i] % 2 == 0) e++;
    }
    if (e == 0) {
      if (n == 1)
        cout << -1 << endl;
      else
        cout << 2 << endl << 1 << ' ' << 2 << endl;
    } else {
      cout << 1 << endl;
      for (long long i = 0; i < n; i++) {
        if (a[i] % 2 == 0) {
          cout << i + 1 << endl;
          break;
        }
      }
    }
  }
}
