C) Congress passes a law to ensure all people have the right to vote.
The Fifteenth Amendment was a law passed by Congress to explicitly guarantee the right to vote for all citizens of the United States, regardless of their race, color, or previous condition of servitude. This amendment aimed to reconcile the discrepancy between American ideals, such as equality and democracy, and the discriminatory public policy that had previously denied or limited voting rights based on those factors. By enacting this law, Congress sought to protect and uphold the principles of equality and democracy in the United States.