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