If it's not an audit, flag it as spam. That gets it into the "spam handling system". You can also leave a comment to alert other readers if it isn't obvious spam (some spam is obvious at a glance, and some is recognizable only if you read through it and maybe do some additional checking). A comment will help other readers recognize it who might not otherwise take the time to dig into it. But, of course, only leave a comment if you are sure it's spam.
Back on the review page, you don't want to select the Delete or Edit option because we need to educate the spam bot.
"Looks OK" might seem like an OK option (you've already done everything you can do, what difference does it make in the review queue?). Here's the problem. There are a limited number of places where answers get exposed to flagging by alert readers. On the main page, everything is posted under the question, so answer content and downvotes aren't visible, and can't alert readers to spam. It is seen by the readers who happen to view the answer, potentially by 10K+ users who happen to see it in the Moderation Tools, potentially or eventually by moderators, but mainly by people in the review queues (that's where the spam flag sends it). Multiple A few "Looks OK" clicks (I believe three), takes the post out of the review queue.
So the only real option is to click Skip.
If it is an audit, and it was really a spam answer, it's already gone. The audit system is just to make sure that you're awake and paying attention, it isn't really about being right (there are endless cases of bad audit examples and logic). If you recognize that it's an audit, just play along with the game (passing means you're paying attention). The "correct" response to spam (even though it's the wrong real response), is to click on Delete. You can't win this one. If you click Skip on general principles, you will remain "due for an audit", so you will continue to get audits until you deal with one (probably not the next review post, but soon).