If you remove the first one, then you can build an argument for any of them - the first because it has no border, the second because it is the only round one, the third because it is green, and the last because it is a different size.
Just because someone can invent a puzzle, doesn’t mean that there is some deep truth in them. Some puzzles are just poorly constructed.
I guess if you’re applying for a front-end web dev position, then the non-bordered square is the odd one out… it’s missing a “class” hahaha.
Now, if you’re a carpenter/builder, then that circle will be the odd one. You’d need a lathe machine to construct that cylindrical rod! (assuming you’re looking at the cross section of all these pieces).