Which of the following pieces of evidence, if true, would provide the best explanation for the apparent discrepancy? A. The margin of error for the survey was plus or minus five percentage points. B. Fifteen percent of the survey's respondents were living overseas at the time of the election. C. Prior research has shown that that people who actually do vote are also more likely to respond to polls than those who do not vote. D. Many people who intend to vote are prevented from doing so by last-minute conflicts on election day or other complications. E. Some people confused the national election with other recent elections when responding to the poll.