—Daddy, will you come home for supper with us today?

—_________ , but I might be a little late.

A．I’m busy

B．No problem

C．It’s a pity

D．It’s hard to say

20℃某A物质饱和溶液在温度不变的条件下，蒸发掉20g水，有5gA析出，则此温度下蒸发掉100g水应析出A物质（）g。

A.25

B.20

C.10

D40