“Who Moved My Cheese?”, ________ best-selling book, is written by Spencer Johnson.

A.it is a

B.that is a

C.a

D.which is

答案及解析： C

解析：

此处可用同位语形式或非限制性定语从句表达。选C，说明是同位语；若用定语从句，则用which is a．