单项选择题

Questions 21 to 23 are based on the following news. At the end of the news item, you will be given 15 seconds to answer the questions. Now listen to the news.
Why were hundreds of cattle slaughtered in Brazil

A.Because they have got the hoof-and-mouth disease.
B.Because they would be exported to Europe.
C.Because there was no food for them.
D.Not mentione