This is a "Strengthen the Conclusion" question. The passage concludes that Domingo is a
prodigy, able to recognize when any instrument is out of tune, on the basis of Domingo’s positive recognition of each instance in which an instrument was indeed out of tune. However, the analysis is not complete without the “flipside” of the test: namely, Domingo also must not have misidentified as “out of tune” any instance in which the orchestra was, in fact, playing in tune. In other words, the passage states definitively that Domingo had no “false negatives” in his identifications, but we are not assured that Domingo had no “false positives”.
(A)
The relationship between the seating of the orchestra and the tuning of the instruments is at best unclear. If the traditional arrangement decreases the difficulty of identifying tuning errors, then this statement actually weakens the passage somewhat; if the traditional arrangement increases the difficulty of identifying tuning errors, though, then this statement strengthens the passage somewhat. Since we have no information from which to make either inference, this statement is inconclusive.
(B) Correct
This statement strengthens the passage’s conclusion considerably, since it provides needed evidence against the possibility of “false positives” in the test. The passage states that Domingo never failed to identify any actual tuning errors, but we need this additional information – that Domingo also never made the inverse type of mistake – to confirm the accuracy of Domingo’s performance.
(C)
The proficiency of the musicians in actual concerts has no impact upon the validity of the test, in which those musicians committed tuning errors on purpose.
(D)
If anything, this statement actually weakens the passage, since it implies a nonrandom pattern to the errors committed as part of the test. If those errors were nonrandom, then any patterns may have artificially helped Domingo identify the errors.
(E)
The relationship between the acoustics of the concert hall and the tuning of the instruments is at best unclear. If the empty concert hall decreases the difficulty of identifying tuning errors, then this statement actually weakens the passage somewhat; if the empty concert hall increases the difficulty of identifying tuning errors, though, then this statement strengthens the passage somewhat. Since we have no information from which to make either inference, this statement is inconclusive.