—Which of those electronic dictionaries do you like most?

—     .They are expensive and of little use.

A．None

B．Neither

C．All

D．Both

造成深覆盖的可能病因是（）.

A.遗传因素引起的上、下颌发育不良或牙量骨量不调

B.长期口呼吸

C.吮指或咬下唇等不良习惯

D.牙萌出顺序异常

E.以上都是