I want to know what _____. [ ]

A. wrong is

B. is wrong

C. the matter

D. is matter

固定桥受力后，基牙会产生负重反应，故要求固定桥的基牙应该是

A．牙冠长而大，形态正常
B．牙体组织健康
C．牙周条件好
D．活髓基牙
E．与邻牙接触关系良好