#include <bits/stdc++.h>
using namespace std;
long long n, k, m;
long long T, ans;
void solve() {
  cin >> n;
  bool first = 0;
  long long id;
  for (int i = 0; i < n; i++) {
    long long x;
    cin >> x;
    if (x % 2 == 0) {
      first = 1;
      id = i;
    }
  }
  if (first == 1) {
    cout << "1\n";
    cout << id + 1 << "\n";
  } else if (first == 0) {
    if (n == 1)
      cout << "-1\n";
    else {
      cout << "2\n";
      cout << "1 2\n";
    }
  }
}
int main() {
  long long t = 1;
  cin >> t;
  while (t--) solve();
}
