White’s best response is clearly 2.exd5. However Black must be ready to handle other second move options from White, e.g. 2.e5 or 2.Nc3, or 2.d3.
If White declines the gambit pawn with 2.e5, Black can counter with 2… c5. Now whether, White plays 3.d4, 3.c3, 3.f4, or 3.Nf3, Black can set up a superior French Defense formation because his Queen Bishop is not hemmed in by the King Pawn on e6. e.g.:
If White declines the gambit with 2.d3, then:
1.e4 d5 2.d3 dxe4 3.dxe4 Qxd1+ 4.Kxd1 Nc6 with some advantage for black
To be continued…
The best way for White to play the Center Counter Game is to accept the gambit and take the pawn on d5, i.e. 2.exd5. Black’s two best replies are either 2…Qxd5 or 2…Nf6. Here a few examples on how to play: