This is a followup to my previous, more general question.
I installed (exposed) 2"x4" studs at strategic locations. These provide a mounting point for metal boxes, and EMT carries the wire up from the crawlspace, through the metal boxes, and up to ceiling height.
Example: (click for full-size)
I want to wire light fixtures in the ceilings. Bending EMT between fixtures' boxes is one option, but because of the unusual shape of the ceiling, I think I'd rather use something flexible. I believe the options are:
NM cable (aka Romex).
AC cable (aka BX).
I think NM is prohibited by code because the rafters are exposed - the cable needs to be protected, right?
Which is the right choice?