What effect did the assassination of Ngo Dinh Diem have on U.S. support in South Vietnam?
A. The assassination put pressure on the U.S. government to take on a more active role in South Vietnam.
B. The assassination gave the U.S. government an opportunity to support a new military government in South Vietnam.
C. The assassination gave the U.S. government an opportunity to pull out all troops from South Vietnam.
D. The assassination put pressure on the U.S. government to support reunification of Vietnam.