#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    int N;
    cin >> N;
    int n = 0, m = 0;
    int j = 0, k = 0, l = 0;
    for (int i = 1; i <= N; i++) {
      int x;
      cin >> x;
      if (x % 2 == 0) {
        m++;
        l = i;
      } else {
        n++;
        if (!k && !j)
          j = i;
        else if (!k && j)
          k = i;
      }
    }
    if (m)
      cout << 1 << endl << l << endl;
    else if (n > 1)
      cout << 2 << endl << j << ' ' << k << endl;
    else
      cout << -1 << endl;
  }
  return 0;
}
