Which of the following best describes the effect of the Vietnam War on the US economy?

Which of the following best describes the effect of the Vietnam War on the US economy?
a. The billions that the United States spent eventually caused a recession.
b. Massive government spending stimulated the economy.
c. The billions that the United States spent devastated the US economy until the early 1970s.
d. There was no real effect on the US economy due to the Vietnam War.