The correct answer is C) Reconstruction.
Reconstruction is the 12 years after the Civil War in which the Union regains the states that were considered the Confederacy during the Civil War. One of the most important questions during this era was how would these states be received? Ultimately, the South faces some consequences but the main action taken revolves around the federal government. The federal government ensures that the laws of the US are enforced in the Southern states. This includes getting rid of slavery, allowing African-American men to vote in elections, etc. The federal government uses different agencies, like the Freedman's Bureau, to help African-Americans adjust to life as free men.