----are they ?--Just $30.A. How muchB. How manyC. WhatD. How

问题补充：

----are they ? ----Just $30.

A. How much

B. How many

C. What

D. How

答案：

(答案→)A. How much

B. How many

C. What

D. How

解析：三个选项分别表示多少钱，多少个，什么和怎样，根据答语仅仅三十美元，可知选A。