#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int t;
  cin >> t;
  while (t--) {
    long long int n, a, count_e = 0, count_o = 0, sum = 0, i, flag = 0, ind;
    cin >> n;
    vector<int> v;
    vector<int> even;
    vector<int> odd;
    for (i = 1; i <= n; i++) {
      cin >> a;
      v.push_back(a);
      sum = sum + a;
      if (a % 2 == 0) {
        count_e++;
        flag = 1;
        ind = i;
        even.push_back(i);
      }
      if (a % 2 != 0) {
        count_o++;
        odd.push_back(i);
      }
    }
    if (flag == 1) {
      cout << "1\n";
      cout << ind << "\n";
    } else if (sum % 2 == 0) {
      cout << n << "\n";
      for (int j = 1; j <= n; j++) {
        cout << j << " ";
      }
      cout << endl;
    } else if (count_o >= 2) {
      cout << "2\n";
      cout << odd[0] << " " << odd[1] << "\n";
    } else {
      cout << "-1\n";
    }
  }
}
