--Do you like these yellow shoes?

--Yes,      

A．I don't like them

B．I'll take it

C．I'll take them

D．it's 5 dollars

将免疫球蛋白分为五类是根据（）

A.轻链恒定区抗原性的差异

B.重链恒定区抗原性的差异

C.Fab段抗原特异性的差异

D.Fc段抗原特异性的差异

E.铰链区抗原的差异