Which event most directly contributed to the end of U.S. involvement in Vietnam?

The U.S. military conducted a raid and massacre in the village of My Lai.

U.S. public opinion against the war became very high during an election year.

Nixon transferred control of most of the fighting to a strong South Vietnamese army.

Violent protests erupted against the war and took place at the Democratic National Convention.

Question

Which event most directly contributed to the end of U.S. involvement in Vietnam?

 The U.S. military conducted a raid and massacre in the village of My Lai.

 U.S. public opinion against the war became very high during an election year.

 Nixon transferred control of most of the fighting to a strong South Vietnamese army.

 Violent protests erupted against the war and took place at the Democratic National Convention.

anonymous · Answer

i know its not A

anonymous · Answer

http://www.infoplease.com/encyclopedia/history/vietnam-war-us-involvement.html Maybe C?