— What have you done these days?— I’ve read all the books you gave me because they are th

问题补充：

— What have you done these days?

— I’ve read all the books you gave me because they are the best ones are on the subject.

A. that; that

B. which; which

C. what; which

D. who; what

答案：

(答案→)A. that; that

B. which; which

C. what; which

D. who; what

解析：考察定语从句。当先行词是指物且前面有all和形容词最高级修饰的时候，都是使用关系代词that。故Ａ正确。