单项选择题

Questions 21~24 are based on the following news from the BBC or the VOA. At the end of the news item, you will be given 20 seconds to answer the two questions. Now listen to the news. According to the opponents, what does free-trade lead to

A.Lower wages.
B.Degradation of the environment.
C.Degradation of labor standards.
D.All of the above.