#include <bits/stdc++.h>
using namespace std;
int main() {
  int t, n;
  scanf("%d", &t);
  while (t--) {
    int id;
    int ans = 0;
    scanf("%d", &n);
    vector<int> a(n + 5);
    for (int i = 1; i <= n; i++) {
      scanf("%d", &a[i]);
      if (a[i] % 2 == 0 && ans == 0) {
        id = i;
        ans++;
      }
    }
    if (n == 1 && a[1] % 2 == 1) {
      printf("-1\n");
      continue;
    }
    if (ans == 0) {
      printf("2\n");
      printf("1 2\n");
    } else
      printf("1\n%d\n", id);
  }
  return 0;
}
