Answer:
The correct answer is c) Groups like the Ku Klux Klan and the White League worked to restore white supremacy in the South through threats and violence against free blacks and white Republicans.
Step-by-step explanation:
The group called Ku Klux klan was one of the white supremacy movements that, together with the White League, were known as terrorist groups, which opposed black people having civil and political rights.
These groups were responsible for intimidating African-American people, especially in the south of the country; they are believed to be responsible for many deaths, including the Colfax massacre, to persuade people with black skin and white skin who agreed with the new policies.
These groups thought that power should only belong to whites and that no other person had to try to obtain a prominent position.
I hope this information can help you.