#include <bits/stdc++.h>
using namespace std;
const int N = 101;
int a[N];
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
      cin >> a[i];
    }
    if (n == 1) {
      if (a[0] % 2 == 1) {
        cout << -1 << endl;
      } else {
        cout << "1\n1" << endl;
      }
      continue;
    }
    if (a[0] % 2 == 0) {
      cout << "1\n1" << endl;
    } else if (a[1] % 2 == 0) {
      cout << "1\n2" << endl;
    } else {
      cout << "2\n1 2" << endl;
    }
  }
  return 0;
}
