#include <bits/stdc++.h>
using namespace std;
class TC {
 public:
  void solve() {
    int n;
    cin >> n;
    vector<int> arr(n);
    for (auto &e : arr) cin >> e;
    if (n == 1 && arr[0] % 2 == 1)
      cout << -1 << "\n";
    else if (arr[0] % 2 == 0)
      cout << 1 << "\n" << 1 << "\n";
    else if (arr[1] % 2 == 0)
      cout << 1 << "\n" << 2 << "\n";
    else
      cout << 2 << "\n" << 1 << " " << 2 << "\n";
  }
};
int main() {
  (ios::sync_with_stdio(false), cin.tie(NULL));
  int t;
  cin >> t;
  double start = clock();
  while (t--) {
    TC tc;
    tc.solve();
  }
  cerr << "[*] Time: " << (clock() - start) * 1.0 / CLOCKS_PER_SEC
       << std::setprecision(3) << " s"
       << "\n";
  return 0;
}
