Although the discount stores in Goreville's central shopping district are expected to close within five years as a result of competition from a SpendLess descount department store that just opened, those locations will no stay vacant for long. In the five years since the opening of Colson's, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson's.
B. Increasingly, the stores that have opened in the central shopping district since Colson's opened have been discount stores.
Which of the following, if true, most seriously weakens the argument? 请NN帮忙讲解一下这道题的思路,谢谢~