How did the south try to deny african american voting rights?

Southern governments implemented a series of devices that would stop African-American citizens from voting including:

1) Poll Taxes- This was a certain amount of money an individual had to pay in order to vote. Many African-Americans could not afford these taxes.

2) Grandfather Clauses- This was a law that essentially stated that you were only able to vote if your grandfather voted. When this was first implemented, many African-American citizens were slaves before or their family members were slaves.

3) Literacy tests- These near impossible tests were based on a person's ability to read and write. This was effective when first implemented because many African-Americans did not have formal schooling due to their status as slaves before the end of the Civil War.

Ithink the answer is d but don’t answer it. i need points.