【单选题】

Speaker A: If I were you, I'd ride a bike to work. Taking a crowded bus during rush hours is really terrible.Speaker B: ______
A．Yeah, riding a bike is a healthful activity. Don't you think

B．Yes, you're right. Buses are always very crowded during the rush hours.
C．Thank you for your advice. But my bike has got a flat tyre.
D．Certainly. I don't see Why so many people go to work by bus rather than by bike.