Final answer:
President Harry Truman referred to the allies of Nazi Germany during World War II as the enemies, pointing to the global conflict and threats still active after FDR's death.
Step-by-step explanation:
When President Harry Truman spoke of enemies in the context of World War II after taking office following Franklin Roosevelt's death, he was referring to C. The allies of Nazi Germany during World War II. Truman feared that the Soviet Union's actions, specifically the installation of a communist government in Poland and the demand for large reparations from Germany, could lead to further conflict. Additionally, Roosevelt's policy entailed supporting the Allied nations such as Britain to prevent German and Japanese aggression from threatening global peace and democracy.
The enemies Truman mentioned were not the U.S. political opponents within his own party, alien visitors, or the American public and citizens of the United States. Instead, he was focused on the global threats posed by totalitarian regimes allied with Nazi Germany and the Axis powers, which were still active even following the demise of Hitler and the impending end of World War II.