Question

following the passage of the fifteenth amendment, states attempted to limit voting rights of african americans through
registration quotas.
poll taxes and literacy
tests.
blood tests and genealogy.
state constitutions.

Explanation:

After the Fifteenth Amendment (which prohibited the denial of voting rights based on race, color, or previous condition of servitude) was passed, states used poll taxes (a tax to vote, which disadvantaged poor African - Americans) and literacy tests (often administered in a discriminatory way, like giving harder tests to African - Americans) to limit African - American voting rights. Registration quotas were not a common method. Blood tests and genealogy were not relevant to voting rights restrictions post - Fifteenth Amendment. State constitutions could not override the federal Fifteenth Amendment in terms of basic voting rights denial based on race, but methods like poll taxes and literacy tests were used as loopholes.

Answer:

poll taxes and literacy tests.