The most accurate response is: Southern legislatures enacted Jim Crow laws.
Despite the passage of the Thirteenth, Fourteenth, and Fifteenth Amendments, which aimed to establish and protect the rights of African Americans, many Southern states implemented Jim Crow laws. These laws enforced racial segregation and imposed restrictive measures that disenfranchised African Americans, effectively circumventing the protections offered by the amendments. This systemic oppression continued to inhibit political and social progress for African Americans in the South.