Final answer:
African Americans failed to gain voting rights after the Civil War due to violence, discriminatory laws, and the end of Reconstruction.
Step-by-step explanation:
The correct option that answers the question 'Why did African Americans fail to gain voting rights after the Civil War?' is option A. After the Civil War, African Americans were unable to gain voting rights due to various reasons such as violence and intimidation towards Black voters, the implementation of discriminatory laws in the Southern states, and the end of Reconstruction period in the South.
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