#include <bits/stdc++.h>
using namespace std;
int arr[110], odds[110], even[110], cnto, cnte;
int main() {
  int test;
  cin >> test;
  while (test--) {
    int n;
    cin >> n;
    cnto = cnte = 0;
    for (int i = 1; i <= n; i++) {
      cin >> arr[i];
      if (arr[i] % 2 == 0) {
        even[cnte++] = i;
      } else
        odds[cnto++] = i;
    }
    if (cnte == 0 && cnto == 1) {
      cout << -1 << endl;
    } else {
      if (cnte > 0) {
        cout << 1 << endl << even[0] << endl;
      } else {
        if (cnto < 2) {
          cout << -1 << endl;
        } else
          cout << 2 << endl << odds[0] << " " << odds[1] << endl;
      }
    }
  }
}
