#include <bits/stdc++.h>
using namespace std;
bool isprime(long long a) {
  for (long long i = 2; i <= sqrt(a); i++) {
    if (a % i == 0) return false;
  }
  return true;
}
long long gcd(long long a, long long b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
long long lcm(long long a, long long b) { return (a * b) / (gcd(a, b)); }
long long fact(long long n) {
  long long s = 1;
  for (long long i = 1, s = 1; i <= n; i++) {
    s *= i;
  }
  return s;
}
long long comb(long long a, long long b) {
  return (fact(a) / (fact(a - b) * fact(b)));
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long t;
  cin >> t;
  while (t--) {
    vector<pair<long long, long long>> v, v1;
    long long n;
    cin >> n;
    long long a[n];
    for (long long i = 0; i < n; i++) cin >> a[i];
    ;
    long long i;
    for (i = 0; i < n; i++) {
      if (a[i] % 2 == 0)
        v.push_back(make_pair(a[i], i));
      else
        v1.push_back(make_pair(a[i], i));
    }
    if (v.size() != 0)
      cout << 1 << endl << v[0].second + 1 << endl;
    else if (v.size() == 0 && v1.size() < 2)
      cout << "-1" << endl;
    else
      cout << 2 << endl << v1[0].second + 1 << " " << v1[1].second + 1 << endl;
  }
}
