Answer:
I would think that it would be each of those except the assassination of MLK just because he died doesn't mean that all of a sudden they gave blacks the right to vote.
Step-by-step explanation:
Voting act of 1965 overcame legal barriers at the state and local levels that prevented African Americans from exercising their right to vote
Elmore v Rice conducted a voter registration campaign to open the Democratic Party primary to African Americans.
The banning of poll tax which is the 24th Amendment, the right of all U.S. citizens to freely cast their votes has been secured.