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. Why were the two large jets specially mentioned
A．To show the key role played by the air traffic controller. B．To show the great responsibility of the pilots. C．To give an example of air disasters. D．To show that air travel is far safer than driving a car.