None of the options in Recommend Close seem useful.
Once you're sure it's an audit, anything would be fine.
You could click the link to view the question on the main site to examine the post more thoroughly.
If it is really a spam post that hasn't been deleted yet, flag it as such. Or if it is not spam but otherwise bad but not fitting a close reason, downvote and/or flag accordingly. Maybe even leave a comment if you think the OP could fix the post or would benefit from feedback.
However, if your inspection brings you the realization that you spotted an audit (because the question is deleted already), just go back to the review page and use any close option. The reason does not matter at all and will not be checked. Pretty sure that attempting to edit the post would count as passed too. Just don't click on "Looks OK".