To score in the ninetieth percentile on the GMAT, one must study hard.If ... ...

Which one of the following most accurately describes the weakness in the above argument?
(A) The argument fails to take into account that not all test-prep books recommend studying four hours a day for one month.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Press: Set F - Classification Practice