Which of these measures was specifically designed to limit the voting rights of the black freedmen?

The Voting Rights Act of 1965, signed into law by President Lyndon B. Johnson, aimed to overcome legal barriers at the state and local levels that prevented African Americans from exercising their right to vote as guaranteed under the 15th Amendment to the U.S. Constitution.

15th amendment is the answer.

the grandfather clause

working boots at local festivals

c. more people could read and interpret the bible for themselves