How to solve this 3x3 dots and lines puzzle?

I saw this on a forum and no one knows how to solve it, and it’s driving me crazy. Does anyone know what the solution is and why?
I tried looking at similarities in the columns, rows, and diagonals. I tried comparing everything to the top left or to the middle but that didn’t help either. I tried seeing if there was a special pattern left in the gaps, but that wasn’t helpful either.

Any clues?