#include <bits/stdc++.h>
using namespace std;
int main() {
  int tc;
  cin >> tc;
  while (tc--) {
    int n;
    cin >> n;
    vector<int> a, b;
    for (int i = 0; i < n; i++) {
      int x;
      cin >> x;
      if (x % 2 == 0)
        a.push_back(i + 1);
      else
        b.push_back(i + 1);
    }
    if ((int)a.size() > 0) {
      cout << 1 << "\n";
      cout << a[0] << "\n";
    } else if ((int)b.size() > 1) {
      cout << 2 << "\n";
      cout << b[0] << " " << b[1] << "\n";
    } else {
      cout << -1 << "\n";
    }
  }
}
