#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int t, n, i, j, arr[100];
  cin >> t;
  for (i = 0; i < t; i++) {
    cin >> n;
    for (j = 0; j < n; j++) {
      cin >> arr[j];
    }
    if (arr[0] % 2 == 0)
      cout << 1 << endl << 1 << endl;
    else if (n == 1)
      cout << -1 << endl;
    else if (arr[1] % 2 == 0)
      cout << 1 << endl << 2 << endl;
    else
      cout << 2 << endl << 1 << " " << 2 << endl;
  }
  return 0;
}
