The number of physical retail stores in a city increased from 3,800 in 2013 to 4,500 in 2017. But in recent years, the proportion of physical retail stores in the city's sales has not increased in the entire retail industry. Has dropped. Which of the following is true and cannot explain the above phenomenon? ['The overall sales of brick-and-mortar retail stores in the city have declined significantly in recent years.', 'Overall sales of non-physical retail stores in the city have increased rapidly in recent years.', "The overall sales of the city's retail industry have increased significantly in recent years.", 'The number of non-physical retail stores in the city has grown faster than physical retail stores in recent years.']