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