#include <bits/stdc++.h>
using namespace std;
int main() {
  int test;
  cin >> test;
  while (test--) {
    int n, odd = 0, a = 0;
    cin >> n;
    int arr[n + 1];
    bool even = false;
    for (int i = 1; i <= n; i++) {
      cin >> arr[i];
      if (arr[i] % 2 == 0) {
        even = true;
        a = i;
      } else
        odd++;
    }
    if (even) {
      cout << "1" << endl;
      cout << a << endl;
    } else {
      if (odd >= 2) {
        int b = 0;
        cout << "2" << endl;
        for (int i = 1; i <= n; i++) {
          if (b >= 2) break;
          if (arr[i] % 2 != 0) {
            cout << i << " ";
            b++;
          }
        }
      } else
        cout << "-1" << endl;
    }
  }
  return 0;
}
