c Congress passes a law to ensure all people have the right to vote.
The Fifteenth Amendment was passed by Congress to explicitly state that the right to vote could not be denied based on race, color, or previous servitude. This law was an attempt to reconcile the contradiction between American ideals of equality and democracy with the discriminatory public policies that had previously excluded African Americans from voting. By passing this amendment, Congress aimed to ensure that all citizens would have the right to participate in the democratic process regardless of their race or background.