A or C it’s been a while since I seen this question
The main reason was because of over population in a small confined area. They also moved father out west so they could get more materials or supplies.
"The Indian Reorganization Act improved the political, economic, and social conditions of American Indians in a number of ways: privatization was terminated; some of the land taken was returned and new land could be purchased with federal funds; a policy of tribal self-government was implemented; tribes were allowed to incorporate businesses and credit established to further such business; and education & employment opportunities were greatly enhanced"
Hope this helped :)
Peisistratus was the first Athenian tyrant if that is what you are looking for
