---I think maths is playing a more important part in the new test system. What about you?    --- ______. We should be more devoted to it.

A．No pains, no gains.

B．Fact speaks louder than words.

C．Great minds think alike.

D．Don’t claim to know what you don’t know.

根据我国的货币供应量层次划分，假定广义货币供应量M2余额为107.7万亿元，狭义货币供应量M1余额为31.5万亿元，流通中货币Mo余额为5.6万亿元，则单位活期存款为（）万亿元。

A.25.9 

B.70.6 

C.75.6 

D.102.1