【正确答案】 D

【答案解析】[听力原文]
The Internet, as a means for commerce, did not become reality until the 1990s. Before this time, it was mainly a tool for the army, and a research device for some American universities. Its popularity grew when it proved to become a fast and efficient means to conduct long distance transactions, as well as an effective way to distribute information.
The number one advantage that e-commerce has is its speed. With increased speeds of communication, the delivery time is greatly decreased and that makes the whole transaction more efficient. Also, you can find practically any product available for sale on the Internet. Even more significant is the fact that information appearing on the Internet can be changed extremely rapidly. This enables business owners to inform customers of any changes to the service that you are offering.
The second advantage of the electronic commerce is the opportunity it offers to save one"s costs. By using the Internet, marketing, distribution, personnel, phone, postage and printing costs, among others, can be reduced. You can start doing business for as little as $100. The savings, therefore, are tremendous.
There is no national boundaries in cyberspace. That means you can do business all over the world as easily as you can in your own neighbourhood. Since the Internet connects everyone in cyberspace, information is transmitted at the speed of sound or the speed of light, depending on your connection. Either way, distance becomes meaningless, which makes you able to link to anyone on the globe and anyone the globe can link to you. The ability to provide links makes doing business on the Internet attractive to customers in any part of the world.
It"s true that a potential source of trouble is customer concerns with privacy and security, however, e-commerce is still safer than using credit cards.