Which of the Following Best Explains Why the Turnout Ratio

Which of the following best explains why the turnout ratio, using voting-age population as the baseline, understates the true turnout rate?

A) The voting-age population overstates the size of the baseline because the voting-age population includes adults over 21.
B) The voting-age population overstates the size of the baseline because the voting-age population includes individuals who are ineligible to vote, such as noncitizens and felons.
C) The voting-age population understates the size of the baseline because it excludes noncitizens and felons.
D) The voting-age population understates the size of the baseline because it includes only adults who have previously voted.