#include <bits/stdc++.h>
using namespace std;
void solve();
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int t = 1;
  cin >> t;
  for (int i = 1; i <= t; ++i) solve();
  cerr << "Time taken: " << ((clock() * 1000) / CLOCKS_PER_SEC) << "ms\n";
}
void solve() {
  int n;
  cin >> n;
  std::vector<int> odd, even;
  for (int i = 0; i < n; ++i) {
    int temp;
    cin >> temp;
    if (temp % 2)
      odd.push_back(i + 1);
    else {
      even.push_back(i + 1);
    }
  }
  if (((int)even.size())) {
    cout << 1 << '\n';
    cout << even[0] << '\n';
  } else if (((int)odd.size()) > 1) {
    cout << 2 << '\n';
    cout << odd[0] << " " << odd[1] << '\n';
  } else {
    cout << -1 << '\n';
  }
}
