Mark the letter A, B, C, or D on your answer sheet...

Câu hỏi: Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.
"It's no use talking to me about metaphysics. It's a closed book to me."

A. a subject that I don't understand

B. a theme that I like to discuss

C. a book that is never opened

D. an object that I really love