#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n;
  cin >> n;
  vector<int> v(n);
  for (long long int i = 0; i < n; i++) cin >> v[i];
  int o = 0, e = 0;
  for (long long int i = 0; i < n; i++) {
    if (v[i] & 1)
      o++;
    else
      e++;
  }
  if (o == 1 && e == 0)
    cout << -1 << endl;
  else if (e > 0) {
    cout << 1 << endl;
    for (long long int i = 0; i < n; i++) {
      if (v[i] % 2 == 0) {
        cout << i + 1 << endl;
        return;
      }
    }
  } else {
    int f = 0;
    cout << 2 << endl;
    for (long long int i = 0; i < n; i++) {
      if (v[i] & 1) {
        cout << i + 1 << " ";
        f++;
      }
      if (f == 2) {
        cout << endl;
        return;
      }
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  int t;
  cin >> t;
  while (t--) solve();
  return 0;
}
