Option 2 is necessary due to CBTC being installed on 8th Avenue, Crosstown, Culver, and 6th Avenue will get CBTC, which will require the A, B, C, and D trains to be 100% NTTs.
Also, let's not forget the second phase of SAS, which will require more trains for the Q.
The MTA needs to stop thinking in present tense. Ridership is growing and it will continue to grow due to the large amount of real estate being built in NYC.
Option 2 must be exercised and they need to have a plan to replace the r68's. It takes 7-10 years to purchase, build, deliver and test new subway cars.