grammaticality - "...at the top or bottom" vs "...at the top or the bottom"

I'm a bit confused about the usage of "the" in a list. Even after reading this post, it's not clear to me which of the following is grammatically correct.

"Is the [object] at the top or bottom?"

"Is the [object] at the top or the bottom?"

Or should "at" be distributed as well? (In which case, it seems clear that "the" should appear twice.)

"Is the [object] at the top or at the bottom?"