Answer: D. suspicion and persecution of communists.
Suspicion and persecution of communists was a common feature of the periods that followed the two world wars. After WWI, the fear was mostly due to the Bolshevik Russian Revolution of 1917. People were scared of patriotic movements and revolutions after the trauma of the war. The second scare came after WWII. In this case, the world was also scared of the power of nationalism and ideology after the experience of Nazi Germany. Moreover, the United States saw the Soviet Union as its competition to become the main hegemonic power in the world.