The correct options are
A The US feared that Vietnam will become a superpower.
B The US feared French control.
C Independence of Vietnam would make France a superpower.
The US feared the spread of communism, and they invaded Vietnam in 1965. They used bacteriological weapons and even bombed both North and South Vietnam. The fighters of North Vietnam, trained in guerilla warfare, were not ready to give up that easily. They continued to fight without bowing to the US, and by 1975, American troops began to withdraw from South Vietnam. In 1976, both North and South Vietnam were formally united.