#include <bits/stdc++.h>
using namespace std;
int main() {
  int t, n;
  cin >> t;
  while (t--) {
    cin >> n;
    int x;
    vector<int> even, odd;
    for (int i = 1; i <= n; i++) {
      cin >> x;
      if (x % 2 == 0) {
        even.push_back(i);
      } else {
        odd.push_back(i);
      }
    }
    if (even.size() == 0 && odd.size() < 2) {
      cout << -1 << endl;
    } else if (even.size() > 0) {
      cout << 1 << endl;
      cout << even[0] << endl;
    } else if (odd.size() >= 2) {
      cout << 2 << endl;
      cout << odd[0] << " " << odd[1] << endl;
    }
  }
}
