After 1.d4 Nf6 2.c4 e6 3.a3, what is the best reply?
Assuming that I, as Black, am a Nimzo-Indian Player, there is no hope for a Nimzo now. Would you go for 3...d5 (QGD with no particularly useful a3 move by White), or for 3...c5 aiming for a Benoni-like structure but allowing 4.d5, or with 3...b6 for a Queen's Indian structure? Or something else?
[Title "What is Black's best reply?"] [FEN ""] 1.d4 Nf6 2.c4 e6 3.a3