Which of the following directly violated the intent of the Fifteenth Amendment to the Constitution?

poll taxes

first-class railroad tickets

racially segregated hospitals

racially segregated schools

Poll taxes directly violated the intent of the Fifteenth Amendment to the Constitution.

Explanation:

Poll taxes were an attempt to curtail the voting rights of African Americans, guaranteed by the 15th Amendment after the end of the Civil War. Specifically, poll taxes required the payment of a certain sum of money for people to have the right to vote. As African Americans, at that time, were in general people of limited or no economic resources, poll taxes literally took these people away from voting.

(d.) is the answer