— How long are you staying? — I don’t know..A. That’s okB. Never mindC. It dependsD. It do

问题补充：

— How long are you staying?

— I don’t know..

A. That’s ok

B. Never mind

C. It depends

D. It doesn’t matter

答案：

A. That’s ok

B. Never mind

(答案→)C. It depends

D. It doesn’t matter

解析：交际用语.句意:你准备呆多久?——我不知道。选C，看情况而定，最符合语境。