单项选择题

Questions 11 to 13 are based on the following passage. At the end of the conversation, you will be given 15 seconds to answer the questions.
Now listen to the passage.

Why didn’t the people of Mutton know where the fire had started

A.Because they were wandering about.
B.Because they were trapped.
C.Because the smoke and dust blurred everything.
D.Because they couldn’t find the signs of the fir