12. Clerk: Front desk. May I help you?Guest: Yes! This is Room 1221. The light in our room is not working.Clerk: I’m sorry. I’ll send someone to take a look at it for you right now.Guest: OK, we’ll go out in just moment.Clerk: That’s ok! I’ll let the man know. Thank you!(A)maintenance (B)maintain (C)mainstream (D)mainland