M: I need to use the restroom, but the door is locked. No one is in there, because I already knocked on the door. Can you give me the key? ,F: Well, the restroom is for customers only. So you'll need to buy something.
(A) M: OK. I will buy something. (B) M: I’m sorry, I didn’t understand. Could you repeat a little louder, please? (C) M: OK. I'll look for the keys first. (D) M: OK. I am going to knock on the door first.
A