#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<int> v(n);
    int k = -1;
    int a = -1, b = -1;
    for (int i = 0; i < n; ++i) {
      cin >> v[i];
      if (v[i] % 2 == 0)
        k = i;
      else {
        if (a == -1)
          a = i;
        else
          b = i;
      }
    }
    if (k != -1) {
      cout << 1 << endl;
      cout << k + 1 << endl;
    } else {
      if (a == -1 || b == -1) {
        cout << -1 << endl;
        continue;
      }
      cout << 2 << endl;
      cout << a + 1 << " " << b + 1 << endl;
    }
  }
  return 0;
}
