In the last decade there has been a significant decrease in coffee consumption. During this same time, there has been increasing publicity about the adverse long-term effects on health of the caffeine in coffee. Ttherefore, the decrease in coffee consumption must have been caused by consumers' awareness of the harmful effects of caffeine. Which of the following, if true, most seriously calls into question the explanation above? ['On average, people consume 30 percent less coffee today than they did 10 years ago.', 'The consumption of fruit juices and caffeine-free herbal teas has increased over the past decade.', 'Heavy coffee drinkers may have mild withdrawal symptoms, such as headaches, for a day or so after significantly decreasing their coffee consumption.', 'Coffee prices increased steadily in the past decade because of unusually severe frosts in coffee-growing nations.']