In 1954, after the French were defeated at Dien Bien Phu, Communists controlled all of Vietnam.

Vietnam was divided at the 17th parallel.

an international committee gave Vietnam back to France.

the United States sent troops to Vietnam to remove the Communists.

oh and by the way, I dont want an explanation for your answer, just put which letter it is. I know the strife of the few people 'studying' that're too poor to afford monthly subscriptions for this stuff. be considerate of the future students lol