What role does the idea of a "multiplier effect" serve in Renfrew's explanation of the development of civilization in the Aegean? A. It allows him to argue that the combined effect of individual developments can lead to a major transformation of a social organization. B. It allows him to explain the idea of a positive feedback loop. C. It allows him to explain the inherently conservative nature of societies. D. It allows him to explain how the changes in agriculture, bronze metallurgy, and craft specialization came about.