In the 21st century, with an intensely competitive consumer market, advertisers increasingly used digital technology to call greater attention to products. In 2009, for example, the world's first video advertisements to be embedded in a print publication appeared in Entertainment Weekly magazine. The thin battery-powered screen Implanted in the page could store up to 40 minutes of video via chip technology and automatically began to play when the reader opened the page. For an advertisement to be effective, its production and placement must be based on a knowledge of the public and a skilled use of the media. Advertising agencies serve to orchestrate complex campaigns whose strategies of media use are based on research into consumer behavior and demographic analysis of the market area. A strategy will combine creativity in the production of the advertising messages with canny scheduling and placement, so that the messages are seen by, and will have an effect on, the people the advertiser most wants to address. Given a fixed budget, advertisers face a basic choice: they can have their message seen or heard by many people fewer times, or by fewer people many times. This and other strategic decisions are made in light of tests of the effectiveness of advertising campaigns.
"Advertising." Encyclopedia Britannica. Encyclopedia Britannica Online School Edition. Encyclopedia Britannica, Inc., 2012. Web. 17 Dec. 2012.
Which line from the text supports the inference that successful ads require a good deal of research?
(A) In the 21st century, with an intensely competitive consumer market, advertisers increasingly used digital technology to call greater attention to products.
(B) For an advertisement to be effective, its production and placement must be based on a knowledge of the public and a skilled use of the media.
(C) A strategy will combine creativity in the production of the advertising messages with canny scheduling and placement,
(D) This and other strategic decisions are made in light of tests of the effectiveness of advertising campaigns.​