Which of These Was the First Barrier to Fall in the United

Which of these was the first barrier to fall in the United States' journey towards universal suffrage?

A) Property, tax-paying, and religious requirements were dropped in most states.
B) African Americans were granted the vote.
C) Women were granted the vote.
D) Citizens of the District of Columbia were allowed to vote in presidential elections.
E) People ages 18 to 20 were allowed to vote.