The argument presents a discrepancy between the percentage of survey respondents who reported that they voted in an election (71%) and the percentage of eligible voters who did vote in that election (60%). An explanation of a GRE discrepancy explains why the apparent conflict does
not apply.

(A) If the margin of error is ± 5%, then the 71% figure could be as low as 66% (or as high as 76%). This accounts for less than half of the discrepancy between 71% and 60%.
(B) This choice does not address the stated discrepancy between the percentage of voters who said that they voted and the percentage of voters who actually did vote. No information is given concerning residency requirements so this information is irrelevant.
(C) CORRECT. One explanation for the discrepancy between these two results is the possibility that people who do vote will respond to surveys at a higher rate than people who do not vote; in other words, people who do vote are overrepresented in the survey’s results. This is an additional premise that would explain the higher percentage of individuals polled indicating that they voted.
(D) While this may be true, the poll did not ask people if they intended to vote; rather, it asked people if they had already voted in a past election.
(E) While this may account for some percentage of the discrepancy, the numerical data is not sufficient to explain the entire discrepancy; “some” means “at least one.” In addition, the confused people would not necessarily have responded that they did vote (when thinking about a different election) even though they did not vote in the national election. They could just as easily have reported that they did not vote (when thinking about a different election) even though they did vote in the national election.