--How much are these pants? twenty dollars．A. It isB. ItsC. These areD. They’re

问题补充：

--How much are these pants? -- twenty dollars．．

A. It is

B. Its

C. These are

D. They’re

答案：

A. It is

B. Its

C. These are

(答案→)D. They’re

解析：考察代词。句意；这条裤子多少钱？英语中裤子为复数含义，根据问句的内容，可知答语应该为复数形式，谓语动词应为复数形式。答语中一般用人称代词来指代上文提到的内容，故选D，他们是。