Answer: the answer is B with the passage of the thirteenth amendment
Explanation:The period after the Civil War, 1865 - 1877, was called the Reconstruction period. Abraham Lincoln started planning for the reconstruction of the South during the Civil War as Union soldiers occupied huge areas of the South. He wanted to bring the Nation back together as quickly as possible and in December 1863 he offered his plan for Reconstruction which required that the States new constitutions prohibit slavery.
In January 1865, Congress proposed an amendment to the Constitution which would abolish slavery in the United States. On December 18, 1865, Congress ratified the Thirteenth Amendment formally abolishing slavery.