Well, it's not the Ku Klux Klan, as that was a large group of people who wanted to have slaves all return to their work, I've never heard of C, and we barely touched on D in school. From what I've learned, however, the Freedmen's Bureau helped former slaves by supplying food, providing education and homes, etc.
Answer:
Many people decided to move to urban areas because it gave them more opportunities.
Explanation:
The peloponn war lasted 27 years
