It is the "National Labor Relations Board" that acts as a mediator in disputes between unions and employers, since many people on both sides of the dispute often claim that the other side is acting unjustly, especially when it comes to negotiations.
I believe the answer is C. I know for sure it is not A or B.
I hope my answer helps :)
Answer:
Southern states enacted black codes after the Civil War to prevent African Americans from achieving political and economic autonomy.
