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