Final answer:
Southern states utilized poll taxes, literacy tests, and grandfather clauses to disenfranchise African Americans and maintain white supremacy after 1890.
Step-by-step explanation:
After 1890, Southern states implemented various restrictive measures to deprive African Americans of their voting rights. The methods included imposing a poll tax, which was a fee that had to be paid before one could vote, effectively disenfranchising those who could not afford to pay. Additionally, literacy tests were introduced, which ostensibly measured a person's knowledge but were administered in a biased manner to disqualify African Americans. Also, grandfather clauses were utilized, which allowed individuals to bypass these voting prerequisites if they or their ancestors had voted prior to the enactment of the Fifteenth Amendment, benefiting white citizens as African Americans had not been allowed to vote before that time.