According to the Cambridge and Merriam-Webster dictionaries, a person who takes power by force and rules with total authority is a dictator. A dictator is not elected by the people, and extends his powers into the private lives of the people. He usually enjoys a cult of personality throughout the nation. An example of dictator would be Hitler in Germany between 1933 and 1945.
You should bear in mind that there are two other words which could fit this definiton, with some nuance:
- if this ruler uses its unlimited power unfairly and/or cruelly, it is a tyrant;
- if this ruler came to power through elections which he rigged, and simply rules without any political opposition, it is an autocrat.
The answer is D. A Supreme court Decision to move the Cherokee west of the Mississippi River. Here is text from Wikipedia,
"Indian removal was a genocide in the 19th century whereby Native Americans were forced by the United States government to leave their ancestral homelands in the eastern United States to lands west of the Mississippi River, specifically to a designated Indian Territory (roughly, modern Oklahoma)."
