#include <bits/stdc++.h>
using namespace std;
int main() {
  long long t;
  cin >> t;
  while (t--) {
    long long n, i;
    cin >> n;
    long long c1 = 0, c2 = 0;
    vector<long long> a(n);
    for (i = 0; i < n; i++) {
      cin >> a[i];
      if (a[i] % 2)
        c1++;
      else
        c2++;
    }
    if (!c2 and c1 == 1)
      cout << -1 << endl;
    else {
      if (c2) {
        cout << 1 << endl;
        for (i = 0; i < n; i++) {
          if (a[i] % 2 == 0) {
            cout << i + 1 << endl;
            break;
          }
        }
      } else {
        cout << 2 << endl;
        long long k = 0;
        for (i = 0; i < n; i++) {
          if (a[i] % 2 == 1) {
            cout << i + 1 << ' ';
            k++;
            if (k == 2) {
              cout << endl;
              break;
            }
          }
        }
      }
    }
  }
  return 0;
}
