"The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude."
Fifteenth Amendment to the United States Constitution
What was the main goal of the 15th Amendment?

A) to punish southern states
B) to avoid another Civil War
C) to granting women the right to vote
D) to grant former slaves voting rights