While I have an opinion about AI, I'm not going to say right now what I think this site should do - I'm not a regular of this site, and I don't really know it. This "answer" is regarding option #3, which states "AI Generated answers are treated like all others and no special actions are needed for them
Tl;dr: AI answers that are not clearly listed as AI answers violate the Inauthentic Usage policy, which is part of the Stack Exchange Code of Conduct. This has been confirmed by a SE Community Manager (staff). Per the Moderator Agreement, diamond (i.e., elected or appointed) mods are expected to enforce the CoC. How mods handle AI-content (as a CoC violation) is, to an extent, up to them. But, individual sites aren't really supposed to make policies overriding the CoC. You cannot, for example, make a policy that allows being intentionally rude to other users.
To respond to your comment:
@cocomac My point is that if it was true that an AI generated/edited answer has to have a statement listing it as AI why would one of the choices listed in the post I link be to add a banner stating that AI answers must be noted as such. The fact that it is a choice to turn on for a site suggests that posting AI answers without listing them as such is allowable. That question is saying sites can have a banner saying AI answers are not allowed, AI answers must be identified or no banner at all. You should post an answer explaining why you think they are not allowed without reference.
AI content that is improperly referenced (i.e., not cited as such) is clearly banned, regardless of whether or not there is a banner announcing it. A lack of a banner does not mean something is permitted. It's entirely possible for a site to say "We don't want the banner", and, for example, deciding they will ban all AI content, whether cited or not.