#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j, counter, t;
  cin >> t;
  for (j = 0; j < t; j++) {
    counter = 0;
    cin >> n;
    int a[n];
    vector<int> vec;
    for (i = 0; i < n; i++) {
      cin >> a[i];
      if (a[i] % 2 == 0) {
        counter++;
        vec.push_back(i + 1);
      }
    }
    if (counter) {
      cout << counter << endl;
      for (i = 0; i < vec.size(); i++) {
        cout << vec[i] << " ";
      }
      cout << endl;
    } else {
      if (n == 1)
        cout << -1 << endl;
      else {
        if (n % 2 == 0) {
          cout << n << endl;
          for (i = 1; i <= n; i++) {
            cout << i << " ";
          }
          cout << endl;
        } else {
          cout << n - 1 << endl;
          for (i = 1; i <= n - 1; i++) {
            cout << i << " ";
          }
          cout << endl;
        }
      }
    }
    vec.clear();
  }
  return 0;
}
