How did the communist takeover of North Korea impact U.S. foreign policy?

It led President Truman to drop atomic bombs on Japan.
It prompted President Truman to reinstate the Open Door policy.
It pushed President Truman to expand containment to include Asia.
It convinced President Truman to provide military support to South Vietnam.

Question

How did the communist takeover of North Korea impact U.S. foreign policy?

 It led President Truman to drop atomic bombs on Japan.
 It prompted President Truman to reinstate the Open Door policy.
 It pushed President Truman to expand containment to include Asia.
 It convinced President Truman to provide military support to South Vietnam.

anonymous · Answer

Ok so the separation of Korea was after WW2 so you can cancel out A