Given the task definition and input, reply with output. In this task you are given a small conversation between two persons and 4 options on how the conversation should continue. Your job is to choose the most reasonable option. The conversation and the options are separated by a newline character. Each dialogue in the conversation are separated by a comma. F and M indicate female and male, respectively.

F: How much is the book? ,M: $10 each. ,F: I'd like to buy three of them.
(A) M: This book is $3.50 for a copy, and you'll pay $10 for three. (B) M: I didn't hear you. Please could you tell me again? (C) M: This book costs $10. You need to pay $20 for two. (D) M: This book costs 15 dollars. You need to pay 30 dollars for two.
B