单项选择题

Questions 11 to 14 are based on the following passage. At the end of the passage, you will be given 20 seconds to answer the questions.
Now listen to the passage.
America succeeded in shaping world events over past 40 years probably because of


A. its ability to adapt technology.
B. its ability to take advantage of the capabilities of its people.
C. its ability to compete in the world markets.
D. Both A and B.