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