#include <bits/stdc++.h>
using namespace std;
const long long int MOD = 1000000007;
long long int temp, test = 1;
void testcases() {
  long long int n;
  cin >> n;
  vector<long long int> arr;
  for (long long int i = (0); i < (n); i++) {
    cin >> temp;
    arr.push_back(temp);
  }
  vector<long long int> odd, even;
  for (long long int i = (0); i < (n); i++) {
    if (arr[i] & 1) {
      odd.push_back(i + 1);
    } else {
      even.push_back(i + 1);
    }
    if ((odd.size() == 2) || (even.size() == 1)) {
      break;
    }
  }
  if (odd.size() == 2) {
    cout << 2 << '\n';
    for (auto iter : odd) {
      cout << iter << " ";
    }
    cout << '\n';
    return;
  } else if (even.size() == 1) {
    cout << 1 << '\n';
    for (auto iter : even) {
      cout << iter << " ";
    }
    cout << '\n';
    return;
  }
  cout << (-1) << '\n';
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    testcases();
  }
  return 0;
}
