Answer:
C
Step-by-step explanation:
The general idea was that communism was spreading across Southeast Asia and the Americans did not particularly like that thought so they (and the Australians, South Vietnamese, New Zealanders, Laos, and the Khmer Republic) engaged into a stalemate hot war with the Soviet backed North Vietnamese army (and several other communist guerilla groups from the surrounding areas such as the VC, PRG, and the Khmer Rouge as well as support from the Soviet Union, China, North Korea, and for a while, Communist backed Cambodia). All in all, it was a war against the spread of communism.