#include <bits/stdc++.h>
using namespace std;
long long T, n;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> T;
  while (T--) {
    cin >> n;
    vector<long long> v[2];
    for (int i = 1; i <= n; i++) {
      long long x;
      cin >> x;
      v[x % 2].push_back(i);
    }
    if (v[0].size()) {
      cout << 1 << "\n";
      cout << v[0][0] << "\n";
    } else if (v[1].size() >= 2) {
      cout << 2 << "\n";
      cout << v[1][0] << " " << v[1][1] << "\n";
    } else {
      cout << -1 << "\n";
    }
  }
}
