What Were the MOST Important Results of the Civil War

What were the MOST important results of the Civil War?

A) greatly improved relations with Great Britain and the renewed power of the planter class
B) the decreased power of the federal government and the emergence of a Democratic Congress
C) the idea that the Union was indissoluble and the passage of the Thirteenth Amendment
D) Lincoln's belief that freedom was dead, and states' ability to leave the Union remained undecided
E) the eradication of cholera by the Red Cross and the elimination of racism in America