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. Therefore, 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?
(A) On average, people consume 30 percent less coffee today than they did 10 years age.
(B) Heavy coffee drinkers may have mild withdrawal symptoms, such as headaches, for a day or so after significantly decreasing their coffee consumption.
(C) Sales of specialty types of coffee have held steady as sales of regular brands have declined.
(D) The consumption of fruit juices and caffeine-free herbal teas has increased over the past decade.
(E) Coffee prices increased steadily in the past decade because of unusually severe frosts in coffee-growing nations.
答案是E没有问题，我的confusion在C选项，OG的解释是:
Suppose that the specialty coffees that had their sales hold steady were all caffeine-free coffees; note that nothing rules this out. If this were the case, the explanation would remain plausible.
想问一下，这个explanation would remain plausible 说的是不是原文的因果关系被加强？因为不含咖啡因的咖啡品牌销售保持，其他含的下降了。