单选题 BYD, a Chinese multinational company, was founded in 1995 although it initially focused on manufacturing batteries. Today, it has become a global leader in new energy vehicles because of its strong commitment to innovation. The company's success is largely attributed to its vertically integrated supply chain, which allows it to control production costs efficiently. One of BYD's most notable achievements is its development of electric buses, which are now used in many cities around the world. Because many countries are promoting green transportation, BYD's electric vehicles have gained significant popularity. However, the company does not only produce vehicles; it also manufactures batteries so that it can provide comprehensive energy solutions. BYD's founder, Wang Chuanfu, believes that sustainable development is crucial for the future, so the company invests heavily in research and development. As a result, BYD has maintained a competitive edge in the industry. Looking ahead, BYD plans to expand its global presence, although this will require adapting to different market demands. The company is confident, however, that it will continue to lead the transition to clean energy. Questions小题:What is the main reason for BYD's success in new energy vehicles