How Did the Diem Government in South Vietnam End

How did the Diem government in South Vietnam end?

A) Diem died peacefully in office and was replaced by a more progressive leadership.
B) Diem was removed from power in an American-supported coup and then was murdered.
C) Because of pressure from the United States, Diem resigned from office and fled to Paris.
D) Diem's campaign for reelection failed because he had lost support among the people.