The correct answer is D) Soviet expansionist plans.
After the end of World War II, the United States and Soviet Union emerged as global superpowers. To maintain this reputation, both had aspirations to remain global influences by creating alliances and spreading their ideas to other countries. This was especially the case with the Soviet Union and their system of communism.
This spread of communism worried the United States, as many felt that this system severely limited individual freedoms. To combat this system, the US federal government developed the concept of containment. The goal of this policy was to stop communism from spreading to other countries. This policy would result in the United States getting involved in several different wars (like Korea and Vietnam) over the course of the next 4 decades.
