What is being repaired? A. A heating system B. A computer network C. An elevator D. A photocopier

Câu hỏi :

Question 4 - 6 refer to following conversation:

Hello, Norman. This is Jina calling from the general affairs office. (74) You have probably noticed that there's a problem with the heating on your floor. I wanted to let you know that I have already called a repair company and arranged for the system to be fixed today. (75) The repair workers should arrive by 10 a.m. and they expect to be finished around 3. I told them that this would be perfect as you will be welcoming clients to your office at 4. I know that it's extremely cold today, so (76) I'll come up to your department at around 11 a.m. and give each employee one of our company jackets. This should help to keep them warm until the repairs are done.

4. What is being repaired?