Which of These Led Voter Participation in Elections to Increase

Which of these led voter participation in elections to increase dramatically between 1824 and 1840?

A) The population of the U.S. grew, so the number of voters increased.
B) People who had been migrating were settled and could register and vote.
C) African Americans in the North were given permission and encouragement to vote.
D) Politicians changed campaigning practices, drawing in more voters.
E) Native Americans in the South and West were given permission and encouragement to vote.