Answer:
<em>The falling economy.</em>
Explanation: Hope this helps..
<span>Causes of Vietnam War: ...1946 - Communists in the north begin fighting France for control of the country.1949 - France establishes the State of Vietnam in the southern half of the country.<span>1951 - Ho Chi Minh becomes leader of Dang Lao Dong Vietnam, the Vietnam Worker's Party, in the north. This is not my work!!!!</span></span>
The answer should be D). Hope this helps, and have a great night! <3