Regular American Military Forces First Entered Vietnam in Order to

Regular American military forces first entered Vietnam in order to

A) set the stage for an invasion of North Vietnam.
B) assist in planning a coup against Ngo Dinh Diem.
C) foster political stability and prevent Ngo Dinh Diem's regime from falling to the communists.
D) keep South Vietnam from falling to the communists until after the 1964 election.
E) promote democratic reforms in South Vietnam.