In terms of ridership, it does make more sense for the C to get all 10 car r179's plus r160's from Jamaica. However, the MTA confirmed that the A and C will get the base order of r211's.
Let's not forget that 8th Avenue CBTC will include 59th Street/Columbus Circle, which means that the B and D will need NTTs. Concourse will most likely get a piece of the first option order of r211's.
The open gang way trains have been testing well, so I wouldn't be surprised if the 2nd option will be 100% r211T's. If that is the case, then the E and F trains can keep all the open gangway trains, while the A, B, C, D trains can keep the r211A's, although it's possible for the B to get the r160's instead of r211A's.