Which is correct, Folks?
That rock, which I had accidentally once found on the ground, was magical;
That rock, which I had once accidentally found on the ground, was magical;
That rock, which I accidentally had once found on the ground, was magical;
That rock, which I once had accidentally found on the ground, was magical.
In order to have this question answered wisely, I asked my teacher, but they said, "I haven't got a clue."