In preagricultural societies, social roles were few and were easily predicted for each phase of a person' s life. Accordingly, interpersonal relations, although not always pleasant or fair, were stable and predictable. Modern society, on the other hand, has thousands of different social roles. Technology and consumerism require that each of us fill highly particularized niches, and these niches are differentiating at an astonishing pace. Ttherefore, __ . Which one of the following most logically completes the argument? ['modern society is characterized by greater injustice and unpleasantness than were preagricultural societies', "in modern societies, people must rely on technology to effectively predict and interpret other people's actions", 'interpersonal relations in modern societies are less stable and less predictable than they were in preagricultural societies', 'the most important difference between modern and preagricultural societies is the variety and type of social roles permitted in each']