Although there are a large number of media buying agencies throughout the world, nearly 75 percent of all media buying is conducted by:

Question

Quizplus · Accepted Answer

The statement in the question indicates that 75 percent of all media buying is conducted by six large global agencies or their holding agencies, which implies that the majority of the market is dominated by these entities rather than any specific country or company (such as the WPP group). Therefore, the best choice is A - six large global agencies or their holding agencies.

Although There Are a Large Number of Media Buying Agencies