Answer:
China had become communist in 1949 and communists were in control of North Vietnam. The USA was afraid that communism would spread to South Vietnam and then the rest of Asia. It decided to send money, supplies and military advisers to help the South Vietnamese Government.
Explanation:
"Differences in regional economic development during the 19th century produced the condition that "<span>A The North was the nation's main industrial area" which strained the South." -HistoryGuy
I took this off of another post with the same question and a positively right answer.</span>