Answer:
The correct answer is C. The rising aggression of Hitler.
Step-by-step explanation:
During the first 2 years of World War II, America was neutral in the conflict. Thus, it did not participate in any military operation, nor did it get involved in important geopolitical issues, limiting itself to trading with the allied nations, mainly Great Britain.
However, the rise of Hitler as a totalitarian figure in Europe, and his actions against Jews, gypsies and other minorities were not ignored by the Americans, who considered Hitler as a dictatorial figure, dangerous and contrary to democratic values of the nation.
Thus, the further the conflict progressed, the more America aligned itself ideologically with the allies, without participating militarily but supporting them through the provision of inputs. Finally, after the Japanese attack on Pearl Harbor in 1941, America declared war on the Axis.