Newspaper report: The government' s health department is unable to explain the recent finding that over time a 10 percent increase in the price of cigarettes caused a 5 percent reduction in the number of smokers. This is a surprising finding because cigarettes are known to be highly addictive and numerous studies have demonstrated that an increase in the price of cigarettes almost never causes people to quit smoking. Which one of the following, if true, most helps to explain the finding that the increase in the price of cigarettes reduced the number of smokers? ['The extent to which cigarettes are addictive depends on the brain physiology unique to the human species.', 'The 10 percent price increase followed a recent 15 percent price increase.', 'Previous price increases have also, over time, caused a reduction in the number of smokers.', 'As cigarette prices rise, the annual number of deaths of smokers surpasses the annual number of new smokers.']