The correct answer is A) literacy tests.
Literacy tests were extremely difficult reading exams that citizens had to take in order to vote. These were initially implemented after the passage of the 15th amendment, which gave African American men the right to vote. This law was targeted at newly freed African American men, as it was illegal to teach slaves to read or write in many of the former Confederate states. This was one way in which Southern state governments tried to stop black citizens from voting without violating the 15th amendment.