#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long tc;
  cin >> tc;
  while (tc--) {
    long long n;
    cin >> n;
    vector<long long> V, E;
    for (long long i = 1; i <= n; i++) {
      long long x;
      cin >> x;
      if (x & 1) {
        V.push_back(i);
      } else {
        E.push_back(i);
      }
    }
    if (E.size()) {
      cout << 1 << "\n";
      cout << E.front() << "\n";
      continue;
    }
    if (V.size() < 2) {
      cout << -1 << "\n";
      continue;
    }
    cout << 2 << "\n";
    cout << V[0] << " " << V[1] << "\n";
  }
  return 0;
}
