A、5%. B、10%. C、15%. D、20%. B对话中女士问男士床垫是不是和床架一起出售的，男士回答不是的，但是可以给女士打九折。由此可见。床垫的折扣是10％。

M: Hi, can I help you?
    W: Yes, I like this mattress. It seems pretty firm.
    M: You’re right. This is a very good brand, so you don’t have to worry about its quality.
    W: Does it come with a frame?
    M: Unfortunately, it doesn’t. However, we could offer a 10% discount on that.
    W: That’s an attractive plan.
    M: Yes. If you like it, you should hurry. This promotion ends tomorrow.
    W: Well, I’ll think about it.
    M: OK.
    6. What is the discount on the mattress?
    7. When will the promotion end?