---Would you like to go for a walk with us?

---        , but I’m too busy.

A．No, I can’t

B．Yes, I’m glad.

C．Yes, I’d like.

D．Yes, I’d like to.

献血助人利自己，国家提倡无偿献血。成人每次献血量应该是多少？两次采集间隔期不少于多长时间？