Following the passage of the fifteenth amendment, states attempted to limit voting rights of african americans through ?

The 15th Amendment was the legislation that granted African Americans men the right to vote for the first time in American history. However, most southern states showed resistance to this law and attempted to limit that African American's right through the imposition of poll taxes, which most black people could not pay, literacy tests, which they often failed, and others obstacles so they could not exercise their right to vote, for example, election officials would threaten them with violence, they would tell them that they had gotten the date, time or polling place wrong, that they had filled out an application incorrectly or they had to recite the whole Constitution in order to be allowed to vote.

answer; i believe the correct answer is (4) flip a coin as each participant arrives,heads indicates assignment to the first group: tails indicates assignment to the second group;