Speaker A: May I take this book out？ I need it to work on my paper for Dr. Smiths history

Speaker A: May I take this book out？ I need it to work on my paper for Dr. Smiths history class. Speaker B: ______

A．Sorry, this book can"t be taken out of the bookstore until you have paid for it.

B．Yes, I think so. This book is good reference work for Dr. Smith"s history class.

C．I"m afraid not. The book has been put on reserve by Dr. Smith. Unless you have his permission, he won"t lend it out.

D．I am not very sure. You"d better ask the librarian over there.

请帮忙给出正确答案和分析，谢谢！