The correct answer is D.
In the Reconstruction Era, the 14th and 15th amendments to the US Constitution had been introduced in order to guarantee equal rights for all US citizens, preventing any form of discrimination in terms of race.
The states could not explicitly prevent any citizen from participating in the elections. Still, many Southern states, circumvented the newly established constitutional provisions by implementing new requirements such as literacy tests, payment of poll taxes, property restrictions, etc., that needed to be fulfilled in order to register to vote. These measures excluded mostly black citizens as many were poor and/or illiterate.
Moreover, the grandfather clauses were introduced. These were used so that those whose ancestors were able to vote before the Civil War, could continue doing it wihtout the need of proving that they met the extra requirements: the tests, the poll taxes, etc. These provisions enahnced even more the discrimination against black US citizens.
I believe it was because they owed money
