【单选题】

In this section, you will hear several passages. Listen to the passages carefully and then answer the questions that follow.

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.
What does the speaker mainly discussA．The safety record of the railroad industry.
B．The reasons railroad regulations were changeD、
C．The financing of railroad construction.
D．The evolution of the railroad industry.