Where can I find what option I chose in the Deal with the Bandits quest?

There are four ways to find this out. You can remove all equipment and count your stats.

The second way is by visiting the bandits, starting with the one you most likely helped.

If they have an exclamation mark above their head it means you killed them, if not then they are the bandit you helped. In my case I helped Oak, as the pictures show. You can also re-kill the ones you previously killed for drops if you want.

Another more direct way is to talk with Eramir. One of the conversation options will be about the person you helped.

EDIT:

The fourth and easiest way is to look at your quest log.