#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3f;
long long qpow(long long a, long long b) {
  long long s = 1;
  while (b > 0) {
    if (b % 2 == 1) {
      s = s * a;
    }
    a = a * a;
    b = b >> 1;
  }
  return s;
}
long long qpowmod(long long a, long long b, long long c) {
  long long res, t;
  res = 1;
  t = a % c;
  while (b) {
    if (b & 1) {
      res = res * t % c;
    }
    t = t * t % c;
    b >>= 1;
  }
  return res;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
inline long long read() {
  long long k = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    k = k * 10 + ch - '0';
    ch = getchar();
  }
  return k * f;
}
inline void write(long long x) {
  if (x < 0) x = -x, putchar('-');
  if (x > 9) write(x / 10);
  putchar(x % 10 + '0');
}
long long t, n, a[105], ans, ji, ou, flag;
int main() {
  cin >> t;
  while (t--) {
    cin >> n;
    ans = 0;
    ji = 0;
    ou = 0;
    flag = 0;
    for (int i = 1; i <= n; i++) {
      cin >> a[i];
      if (a[i] % 2 == 0) {
        ou++;
      } else {
        ji++;
      }
    }
    if (ou == 0) {
      if (ji >= 2) {
        cout << 2 << "\n";
        for (int i = 1; i <= n; i++) {
          if (flag == 2) {
            break;
          }
          if (a[i] % 2 == 1) {
            cout << i << ' ';
            flag++;
          }
        }
        cout << "\n";
      } else {
        cout << -1 << "\n";
      }
    } else {
      cout << ou << "\n";
      for (int i = 1; i <= n; i++) {
        if (a[i] % 2 == 0) {
          cout << i << ' ';
        }
      }
      cout << "\n";
    }
  }
  return 0;
}
