The first line is the most frequently played variation or is the main line.The second variation is quite interesting but still its unclear.Third one I believe is better for black (Anderssen var.) In the fouth line,black sacrifices a pawn for rapid development.
44 ( +1 | -1 ) I believe the actual Anderssen variation is 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4.d4 e5 and doesn't quite have the same level of justification as the perfectly good 1. e4 d5 2. exd5 Qxd5 3.d4 e5 line. I'd usually play 4...c6 after 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4.d4, a move order that is designed to avoid various annoying ideas white has. Admittedly it looks a bit slow, but so far I've no discovered any problem with it (hence I think option one is definitely absolutely okay for black).
43 ( +1 | -1 ) short comment on the last lineI ussually don't play c4 to hold the pawn...I play 3. Bb4+ and then if Bd7 hold the pawn with Bc4. The games I have played in this line so far are of low quality full of mistakes and not worth mentioning. Consequently, right now I am trying to reduce the number of games so I can play higher quality games here. But I would like to investigate the 3. Bb4+ line at some point, so if someone is interested in a game send me a message and I will get back to you.