For Which of the Following Reasons Could the Supposed Increase

for which of the following reasons could the supposed increase in voter turnout in the 2004 election really be just an artifact of the way that voter turnout is measured?

A) The turnout rate was based on all residents of voting age.
B) The turnout rate was measured by randomly sampling only a select few polling places.
C) The turnout rate may have included many ballots that were cast illegally.
D) for the first time, the turnout rate was based on eligible voters, as opposed to all residents of voting age.