I read a book again. I had read it before. It was really interesting.

Which sentence combination uses an adjective clause?

A. When I read the book again, I found the same book really interesting.

B. Although I had read the book, I read it again because it was really interesting.

C. I read the same book that I had read, because it was really interesting

D. After reading the book, I read it again; it was really interesting.