According to the passage, the "simple dichotomy" is useful primarily because it serves as A. a way of calling historians' attention to certain facts about the Industrial Revolution B. an antidote to the oversimplification encouraged by such terms as "festival culture" C. a device for distinguishing between the work and the leisure activities of preindustrial Europeans D. a way of understanding the privileged class of medieval Europe by viewing its activities in modern terms E. a tool for separating social history, including the history of leisure, from economic history