Columnist: The advent of television helps to explain why the growth in homicide rates in urban areas began significantly earlier than the growth in homicide rates in rural areas. Television sets became popular in urban households about five years earlier than in rural households. Urban homicide rates began increasing in 1958, about four years earlier than a similar increase in rural homicide rates began. Which one of the following, if true, most supports the columnist's argument? ['The portrayal of violence on television is a cause, not an effect, of the violence in society.', 'There were no violent television programs during the early years of television.', "Increasing one's amount of leisure time increases one's inclination to act violently.", 'The earlier one is exposed to violence on television, the more profound the effect.']