(D) Many people in the U.S. felt that foreign policy should be changed to support containment
In 1949, after the end of WWII, the Soviet Union was growing strong, and many war-torn nations were open to the idea of communism to rebuild. At the time, China had been in a civil war between the Chinese Communist Party (CCP) led by Mao Zedong, and the Nationalist Party. As corruption, continuing distrust and lessening support in the Nationalist Party rose, it led to Zedong and the CCP's victory in China.
This, and the communist revolutions or other nations led the U.S. to start a containment campaign of communism, and eventually led to the Cold War, and the sour relations between the U.S. and Russia, as both tried to convert nations to their forms of government (U.S. - Democracy / Russia - Communism)