The national association for the advancement of colored people (NAACP) was the union that was opened to African-Americans.
Answer:
O the Thirteenth Amendment
Explanation:
The Thirteenth Amendment (Amendment XIII) to the United States Constitution abolished slavery and involuntary servitude, except as punishment for a crime. In Congress, it was passed by the Senate on April 8, 1864, and by the House on January 31, 1865.