ECN Forum Forums Code Related Discussion NEC & other Code issues 12/2 MC Allowed NYC or Code requires AC only

From out of NY.
Roughing in outlets in a basement in NYC.
Couple of questions:

1- Is MC 12/2 with a separate green ground ok? Or does it have to be AC 12/2 with cable as ground?
(I was advised 12/2 AC with the AC as a ground is no longer acceptable and it must be MC with separate green wire)

2- On a 20A circuit is 10 outlets per circuit acceptable?

3- Roughing in a 10/3 30A line for an AC or heater. Can regular BX/AC box be used or does it have to be a larger square box with separate connectors.

Thanks.

LW