Whihol the holowing科the best eample of an open questiont以下哪个是开放问题的最好时子?

A.Does this exercise hurtr这个运动困维吗?。

B.Why do you want to lose 20 pounds?r“你为什么想要减掉20磅?

C.Ae you ready to get started totay?“你准备好今天开始了吗?。

D."Are you leing okayr“你感她好吗?”