A) Nothing, just totally naked
B) What you’re wearing and anything you carry with you (even if you’re not carrying it right now) like a bag
C) What you’re wearing, what you carry with you, and the contents of your home (it will be teleported within a few hundred metres on the surface in an accessible location, but obviously won’t be connected to any services like electricity or water)
Eh, cut them some slack. When the Spanish showed up sitting on top of wild animals, covered in metal and on an impossibly, comically large boat, the Aztecs toyed with the idea it was something supernatural, but figured out it was just more assholes pretty quickly. In this scenario, you’re merely weird-looking and unintelligible.