A、Three days ago. B、Four days ago. C、Five days ago. D、Six days ago. D对话中女士提到书过期后每天的，罚款是25美分，而这位男士共需要付1.5美元的罚款，所以应该是过期了6天。故本题答案为D

W: Where is the bus? It was scheduled to be here about thirty minutes ago. And I’m already late for work.
M: Me, too. I hate riding the bus. It’s never on time, and we have to be at a bus stop for hours no matter how the weather is.
Q: What are they talking about?

M: Can you help me with returning my late book?
W: This is the right spot to pay your fee. Put your book down right here. I can see that you owe 25 cents a day, and that will be one dollar and fifty cents in all.
Q: What was the expiry date on the man’s book?