Educators are pleased with the recent rise in median SAT scores, which occurred after a decade of decline. Unfortunately, this encouraging statistic actually reflects rather poorly on our educational system. The scores have gone up because fewer students take the tests. A lot of disadvantaged students have simply given up hope of going to college, so they don't bother to take the tests (which they would need to get accepted). In other words, students who have tended to get low scores in the past have dropped out of competition entirely. The higher median scores now are the result of having only privileged, college-bound students take the test.
The author argues primarily by
A. denying the accuracy of his opponents' figures
(A) is incorrect because the author does not dispute the fact that SAT scores have recently gone up. The dispute is over what these figures mean, not what they are.
B. finding an alternative explanation for his opponents' evidence
(B) is correct. The author attributes the rise in SAT scores to the fact that fewer students take it, the ones who have been inclined to do poorly are the ones who are no longer taking it at all, and the only ones taking it are the ones who are inclined to do well. His opponents, on the other hand, seem to think that the higher scores indicate that the schools and the students' education have improved. The author therefore draws a different conclusion from the same facts.
C. refining and clarifying an existing argument
(C) is incorrect, because there's no "existing argument" for the author to refine or clarify. The author is disputing his opponents' conclusion, not updating his own position.
D. defending an argument against criticism by his opponents
(D) is incorrect because there's no indication that the author has been criticized by his opponents. The author's argument is presented as a new idea, an alternative to the standard interpretation of the results, based on conditions his opponents may not have considered.
E. suggesting that his opponents may be unfairly biased
(E) is incorrect because there is nothing in the stimulus to suggest that the author thinks his opponents' conclusion is unreasonable. Although the author may imply that his opponents neglected to consider the additional facts he proposes, he does not imply that they have done so for selfish, dishonest or emotional reasons.
