求助！OG上的一道逻辑题！

陌下清风

  Although the discount stores in Goreville's central shopping district are expected to close within 5 years as a result
  of competition from a SpendLess discount department store that just opened, those locations will not stay vacant
  for long. In the 5 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
  which of the following, if true, most seriously weakens the argument?
(A) Many customers of Colson's are expected to do less shopping there than they did before the SpendLess store opened.
(B) Increasingly, the stores that have opened in the central shopping district since Colson's opened have been discount
      stores.
(C) At present, the central shopping district has as many stores operating in it as it ever had.
(D) Over the course of the next 5 years, it is expected that Goreville's population will grow at a faster rate than it has
      for the past several decades.
(E) Many stores in the central shopping district sell types of merchandise that are not available at either SpendLess or
     Colson's.

这道题的答案为（B）          我的理解是开始一直在说Spendless与discount stores的关系，后来转到了Colson's上与discount stores的关系上。
                                          那这个Spendless在文章里管什么用？我感到好乱啊.....希望有人给我解释解释这里边的逻辑关系，谢谢~

哦买嘎

纯属个人想法：
G 中的d-stores会在未来5年中因为刚开的 S dd store而倒闭，但这些地方不会空闲太久的。 作者的论证是 他说因为有一个叫C的non ds，  在这5年中在每一个因竞争不过C而倒闭的地方都又开了一间新店（注意原文只是说a new store）。
B答案： C开业后的新店很多都是ds。 那不正说明了新开的店都是会在五年中倒闭的，所以位置会空闲