听力原文： Andrew Carnegie, known as the King of Steel, built the steel industry in the United States, and, in the process, became one of the wealthiest men in America. His success resulted in part from his ability to sell the product and in part from his policy of expanding during periods of economic decline, when most of his competitors were reducing their investments. Carnegie believed that individuals should progress through hard work, but he also felt strongly that the wealthy should use their fortunes for the benefit of society. He opposed charity, preferring instead to provide educational opportunities that would allow others to help themselves. 'He who dies rich, dies disgraced,' he often said. Among his more noteworthy contributions to society are those that bear his name, including the Carnegie Institute of Pittsburgh, which has a library, a museum of fine arts, and a museum of national history. He also founded a school of technology that is now part of Carnegie-Mellon University. Other philanthropic gifts are the Carnegie Endowment 'for International Peace to promote understanding between nations, the Carnegie Institute of Washington to fund scientific research, and Carnegie Hall to provide a center for the arts. Few Americans have been left untouched by Andrew Carnegie's generosity. His contributions of more than five million dollars established 2,500 libraries in small communities throughout the country and that we all enjoy today. Which of the following accounts for Andrew Carnegie's success?