The correct answer is C.
The Twenty-Fourth Amendment prohibits the right to vote based on a poll tax. The poll tax was adopted in the first place as a way to exclude poor African Americans from voting. With the ratification of this Amendment in 1964, another milestone in the battle for equal rights as part of the Civil Rights Movement was established.
The Voting Rights Act of 1965 prohibits racial discrimination in voting. The Act secured the right to vote for racial minorities throughout the country, especially in the South. It is also considered to be the most effective piece of federal civil rights legislation ever.
Both the Twenty Fourth Amendment and the Voting Rights Act were part of the overall Civil Rights Movement, a struggle to ensure equal constitutional rights for African Americans.