How did the 15th ammendment affect elections in the south?

The 15th Amendment, granting African-American men the right to vote, was formally adopted into the U.S. Constitution on March 30, 1870. Passed by Congress the year before, the amendment reads: “the right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude.” Despite the amendment, by the late 1870s, various discriminatory practices were used to prevent African Americans from exercising their right to vote, especially in the South. After decades of discrimination, the Voting Rights Act of 1965 aimed to overcome legal barriers at the state and local levels that denied blacks their right to vote under the 15th Amendment.

the correct answer is b