I'm not sure that's fair about question 2. It's hard to say because I know python (but not the deque class), but none of the incorrect answers seem like they'd

I'm not sure that's fair about question 2. It's hard to say because I know python (but not the deque class), but none of the incorrect answers seem like they'd be correct in any sensible language. Like, whatever language you're using, you need to push the children of the current node on to the queue. Only one answer looks like it could reasonably do that.