It can be inferred from the passage that a historian who wished to compare crime rates per thousand in a European city in one decade of the fifteenth century with crime rates in another decade of that century would probably be most aided by better information about which of the following? A. The causes of unrest in the city during the two decades B. The aggregate number of indictments in the city nearest to the city under investigation during the two decades C. The number of people who lived in the city during each of the decades under investigation D. The mental attitudes of criminals in the city, including their feelings about authority, during each of the decades under investigation E. The possibilities for a member of the city's nonelite to become a member of the political and social elite during the two decades