#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1.0);
const double EPS = 1e-8;
const long long MOD = 1000000007;
const int N = 100000 + 7;
int tc, n, x;
vector<int> even, odd;
int main() {
  scanf("%d", &tc);
  while (tc--) {
    even.clear(), odd.clear();
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
      scanf("%d", &x);
      if (x & 1)
        odd.push_back(i + 1);
      else
        even.push_back(i + 1);
    }
    if (even.size())
      printf("1\n%d\n", even[0]);
    else if (odd.size() > 1)
      printf("2\n%d %d\n", odd[0], odd[1]);
    else
      puts("-1");
  }
  return 0;
}
