First of all, vote! The voting buttons suggest:
- Upvote = Answer is useful
- Downvote = Answer is not useful
Use them accordingly.
Secondly, there are no "shared first places" when it comes to accepting answers. So, pick the one that was most useful/helpful to you. This may differ from the criteria you laid out when asking the question. It's your choice.
Finally, if you feel like you still owe someone a reward for not picking their answer, you can always issue a bountyissue a bounty.