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.
The best option from the list would be that "It convinced President Truman to provide military support to South Vietnam," since the US thought that this would be the best way to contain the spread of communism.
