GMAT Critical Reasoning (CR) | Re: Reading skills among high school students in Gotham have

Reading skills among high school students in Gotham have been steadily declining, which can only be the result of overcrowding in the schools.

Which of the following, if true, most seriously weakens the argument expressed above?

a) The high school system in Gotham succeeds in giving students a good education at considerably less cost than do most systems.
b) Several cities have found that overcrowding in the schools is not always associated with lower reading scores.
c) Gotham schools have