下述哪一项不属于抗凝系统（）

A.抗凝血酶Ⅲ（AT－Ⅲ）

B.蛋白C系统

C.组织因子途径抑制物（TFPI）

D.肝素

E.t－PA

-Jenny took the 8：00 bus to Guangzhou this morning.

-Really? He＿＿the 9:00 train. It's much more  comfortable and safer to travel by train.

A．could have taken

B．should take

C．must have taken

D．can take