#include <bits/stdc++.h>
using namespace std;
int a[105];
void solve() {
  int n, ans = 0;
  cin >> n;
  int ok = -1;
  for (int i = 1; i <= n; i++) {
    cin >> a[i], ans += a[i];
    if (a[i] % 2 == 1) ok = i;
  }
  if ((ans % 2 == 1 && ok == -1) || (ok != -1 && n == 1)) {
    cout << -1 << endl;
    return;
  }
  if (ans % 2 == 1) {
    cout << n - 1 << endl;
    for (int i = 1; i <= n; i++)
      if (i != ok) cout << i << " ";
    cout << endl;
  } else {
    cout << n << endl;
    for (int i = 1; i <= n; i++) cout << i << " ";
    cout << endl;
  }
}
int main() {
  int t;
  cin >> t;
  for (int i = 0; i < t; i++) {
    solve();
  }
  return 0;
}
