A、He will further examine the cause of the problem. B、He will ensure the quality of the mushrooms. C、He will take action to chan

W: Mr. Brown, I’d like to talk to you about something that is getting to be a problem. I’d like, if possible, to see it settled at this meeting.
M: What is it, Mrs. Green?
W: It’s about the quality of 300 cartons of dried mushrooms. They reached us two weeks ago, and were immediately examined after they arrived. (12)To our astonishment, about 20% of them had gone bad.
M: Is that so? So far we haven’t had any complaint of this kind. (13)Our mushrooms have enjoyed a good reputation for their superior quality for years. As you know, before shipment, the Commodity Inspection Bureau inspected the goods in question. They concluded that the goods were well dried from fresh and up to standard for export. We are really at a loss to understand why your lot was found to be bad. Do you have any evidence?
W: Certainly. Here’s a survey report by a well-known lab in London, whose evidence is absolutely reliable.
M: Though everything may be as what you say, there are many factors involved.
W: The mushrooms were packed in small one-pound plastic bags, sixty of these bags to a carton. It is stated on the surveyor’s report that external conditions of goods at the time of survey are all sound. (14)So the mushrooms may not have been dried properly. And it is obvious the cause of the damage.
M: (15) We’ll make further investigation. I assure you we will do everything possible to find out why it happened. Please give us some time.
W: OK. Thanks for your action. Goodbye.
M: Goodbye.
　　12. What problem are the speakers discussing?
　　13. Why have the mushrooms enjoyed a good reputation?
　　14. What may be the main cause of the damage?
　　15. What measures will the man take according to the conversation?