重肝的饮食应为（）

A.足量维生素K

B.高脂肪

C.足量维生素B

D.足量蛋白质

E.足量维生素C

According to the passage, efficiency of e-mail is threatened by ______

A．heavy e-mail traffic

B．fraudulent e-mail messages

C．large volume of messages

D．increasing amount of unwanted e-mail