(I assume it's 'pawn to b4', in which case it should have been noted as 'b'4, not 'B'4... but anyway...)
D4? If you are a Wizard then invest in a Quarterstaff, seriously. If you are any other class you have no excuse for not having something that rolls a larger damage die than that. Get something that rolls a D6 or D8 at least - if you are a Fighter and not dealing at least D10 before strength and magical bonuses then I hope it is because you are a dual-weapon specialist at least!