A、Category system. B、Electronic Yellow Pages. C、Introduction of the location. D、Building up the image. B录音最后一句即是答案所在之处，由此可知B正确。短

Yellow Pages advertising is directory advertising because it tells people where to go to get the product or service. It reaches prospects—people who already know they have a need for the product or service. Directory advertising is the only form of advertising that is actively consulted by prospects who need or want to buy something. Yellow Pages advertising is the most widely used form of directory advertising. It is the most universal of advertising medium. For some small business, the advertising is generated from local businesses. A Yellow Pages ad is the last step in the search for a product or service by a committed consumer. [16]The Yellow Pages are used primarily for comparison shopping.
    Although the advertisement doesn’t have to attract the attention of an indifferent audience, it does have to stand out in a competitive environment. [17]The decision about which store to call or visit will be based on certain criteria, the size of the ad being the first. Larger ads get more attention than small ones. Other decision factors include convenience, range of products or services, and the reputation or image of the store. The most important feature of Yellow Pages advertising is the category system.
    Certain information is critical to Yellow Pages ads including location, hours and graphics. [18]A recent development in directory advertising is the electronic Yellow Pages, a database accessed by computer.
16. What is the basic use for the Yellow Pages?
17. What is the most important design part of a Yellow Pages ad?
18. What is the latest invention in directory advertising?