Final answer:
The Ku Klux Klan was formed D. at the end of the Civil War in 1866, with a subsequent resurgence in 1915 leading to the Second Ku Klux Klan which extended its supremacist campaigns to other minority groups.
Step-by-step explanation:
The Formation of the Ku Klux Klan
The Ku Klux Klan was formed D. at the end of the Civil War, specifically in 1866 in Pulaski, Tennessee. It quickly spread throughout the states that comprised the former Confederacy by 1868.
The KKK was steeped in maintaining white supremacy, often through a campaign of terror which included lynchings, beatings, and murder directed at African Americans and their white allies.
The organization's violent actions were part of a broader wave of post-war retaliation against the newly gained freedoms of African Americans.
Although the KKK became dormant towards the end of Reconstruction in 1877, it saw a significant resurgence with the founding of the Second Ku Klux Klan in 1915.
This new incarnation of the KKK, which increased significantly in membership during the 1920s, was less secretive and broadened its campaigns to target Jews, Catholics, and nonwhite immigrants in addition to African Americans.
Despite its members' participation in social and fraternal activities, they continued to engage in intimidation and violent acts, especially in the South.