Questions 6 and 7 are based on the following news. At the end of the news item, you will be given 10 seconds to answer each of the two questions. Now listen to the news. The strike has broken out in South Africa because ______.
A．more than one hundred miners died 4n a disaster. B．black miners have been calling for a wage rise. C．miners wanted to mourn over colleagues’ deaths. D．miners wanted to better their working conditions.