100/200 A4o on the button

[Paluka]

100/200 6 max on pokerstars. The big blind is an unknown to me, so far hasnt' done anything weird in one trip around the table.
Folded to me, I raise A4o on the button. Big blind calls.

Flop 258 rainbow.

check, I bet, bb checkraises.

3 bet or call? Is this a spot where you want to vary your play? Am I making a move on the turn?

Mostly I'm wondering if one particular line has a lot of EV here, or if the various lines you can take are pretty close and you just want to mix up your play.