Restaurant critic: Most people agree that the food at Marva' s Diner is exceptional, while the food at the more popular Traintrack Inn is fairly ordinary. This discrepancy should come as no surprise, since the Traintrack Inn' s more convenient location is by itself almost enough to guarantee a steady flow of customers . Which one of the following is a principle that, if valid, most helps to justify the restaurant critic's reasoning? ['The best way for a business to attract a steady flow of customers is to improve its products .', 'The quality of the food at a restaurant is the most important factor in its popularity.', "There is no relationship between the quality of a restaurant's food and the popularity of that restaurant.", 'A business will improve its products only when it is necessary to do so in order to attract customers .']