Interstingly enough (A) has the same Advantages phil says of B,(posted 8950 days ago)(A) rewards players with a score of level reached as well just not as much.
(A) also allows you to retain your previous levels score if you happen to make a mistake big time in your last level. With B, You can LOSE almost half you entire previous score if you accedentally put a card at the breaking point, since you have to subtract ALL the cards that are left, potentially 50 cards left times 700 if you reach the 8th level, so if you made it to 8 got 70000 or so points, you would have to take off 50x700 = 35000 if the card went to fast, bringing you score down to half it was previously.
Another disadvantage of B is what do you score