B, it was when the western pioneers moved east to discover new land to grow crops and make population XD
Its either B or C. but if I'm not mistaken its c
Answer:
Containment.
Explanation:
The policy of containment is a foreign policy proposed by the government under the Presidency of Harry S. Truman to limit the powers of the Soviet Union and its spread of communism after World War II in 1947. This policy was a reply to the Soviet Union when it started to expand its communist control in Eastern Europe and Asia. The idea of containment policy was to make countries well-off enough to avoid the lure of the Soviet Union. It provided support for countries that rejected communism. Americans fought on the sides of the nationalists to try to stop the spread of communists.
They started domesticating wheat. This wasn't their main feat however since they also started herding sheep and domesticating goats. These two enabled them to stop moving around like nomads and make a real civilization in the area which resulted in what is now known as history.