in this scenario whichever skill you pick, you immediately become as good as the human that is best at that skill (throughout history or current), without having to spend that time learning.
i feel like i'd choose public speaking because i really admire the people who can think on the spot and eloquently put whatever they are thinking and want to say into a concise/thoughtful response with their internal thoughts flowing directly into clear/understandable/well phrased outward ideas. I feel like it'd be a skill that would be really useful to have.