---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.

运输层的协议是（）

A.FTP

B.TCP

C.RIP

D.NFS