what does the command aaa new-model enable?

By itself, what does the command aaa new-model enable?

A.
It globally enables AAA on the switch, with default lists applied on the VTYs

B.
Nothing; you must also specify which protocol (RADIUS or TACACS) will be used for AAA

C.
It enables AAA on all dot1x ports

D.
Nothing; you must also specify where (console, TTY, VTY, dot1x) AAA is being applied