I went with 100% AI generated option as I believe AI tools can help with grammatical errors, make your own content then proof-read with AI, if you like, it's alright in my opinion.
...and anyhow, these AI tools sometimes show even purely human generated as an AI generated, if one were to go with second option — "If AI is detected, irrespective of what percentage." then genuine users will get caught in crossfire.
Edit: Changed 'often' to 'sometimes'