Fast-food restaurants make up 45 percent of all restaurants in Cantaria. Customers at these restaurants tend to be young; in fact, studies have shown that the older people get, the less likely they are to eat in fast-food restaurants. Since the average age of the Canatrian population is gradually rising and will continue to do so, the number of fast-food restaurants is likely to decrease. Which of the following, if true, most seriously weakens the argument? ['As the population of Canatria gets older, more people are eating at home.', 'The overall population of Canatria is growing steadily.', 'Fast-food restaurants in Canatria are getting bigger, so each one can serve more customers.', 'Many people who rarely eat in fast-food restaurants nevertheless eat regularly in restaurants.']