【单选题】

{{I}}{{B}} Questions 11 to 13 are based on the following passage.At the end of the passage, you will be given 15 seconds to answer the questions. Now listen to the passage.{{/I}}{{/B}} What is the growing danger in air travel according to this passage

A、Crowded air traffiC、
B．The large size of airplanes.
C．Mistakes by air traffic controllers.
D．Bad weather.