— I thought you wouldn't mind.

— Well, ________, I don't; but you should have asked me first. [ ]

A. as a whole  

B. by the way

C. no matter  

D. as a matter of fact

已知在反应3A+2B==2C+D中，反应物A、B的质量比为3∶4。当反应生成C和D的质量共140g时，B消耗的质量为_______g。