Which of the following does the author describe as limited in what it could do?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

${\,\,\,\,\,\,\,}$ In the 20th century, magazines have been a major growth area of popular publishing. Specialist magazines cater to every imaginable field and activity. In the United Kingdom, over 12,000 periodicals, magazines, bulletins, annuals, trade journals, and academic journals are published on a regular basis. There are some 40 women’s magazines and over 60 dealing with particular sports games, hobbies, and pastimes. Although some US magazines, such as The Saturday Evening Post, has succumbed to the circulations, The Reader’s Digest over 16 million, the National Geographic over 10 million. For many people, magazines have been the most available and widely used form of continuing education, providing information about history, geography, literature, science, and the arts, and as well as guidance on gardening, cooking, home decorating, financial management, psychology, even marriage and family life.

${\,\,\,\,\,\,\,}$ Until the rise of television, magazines were the most available form of cheap, convenient entertainment in the English-speaking world. Radio served a similar function, but it was more limited in what it could do. Magazines and television, however, both address the more powerful visual sense. During the third quarter of the 20 century, coincident with a dramatic rise in the popularity of television, many general interest, especially illustrated magazines went out of business. The shift in attention of a mass audience from reading such magazines to watching television has been a major factor in this decline, but it is an implicit tribute to the older genre that its programs are generally organized in a single format and content.