This chart shows the percentages of african americans registered to vote in mississippi from 1964-1982. what best accounts for the great increase in registered voters between 1964 and 1966?
a) all voters in mississippi were finally allowed to vote by mail or by absentee ballot.
b) congressional legislation was passed that made registering to vote safer for african americans.
c) the presidential candidates in 1966 offered more hope and opportunity to african american voters.
d) technological advancements made the registering process quicker and easier throughout the united states.