Final answer:
Fascists employed the theory of social Darwinism to assert racial superiority and justify authoritarian rule. Fascism emerged during the interwar period, rejecting the principles of democracy and communism in favor of nationalism and authoritarian hierarchy. Despite authoritarian tendencies similar to communism, fascism was distinguished by its intense nationalism and racial ideology. The correct option is D. Social Darwinism.
Step-by-step explanation:
The theory fascists used to support their ideology was social Darwinism. Fascism, particularly Nazism, manipulated nationalism and infused it with ideas of racial superiority, directly opposing the principles of democracy and communism. During the interwar period in Europe, the appeal of fascism grew out of disillusionment with democratic governments and a desire to resist communist expansion.
The advent of fascism was characterized by its intense nationalist sentiment coupled with a strict hierarchical society, anti-democratic values, and authoritarian governance. Fascism's promise of national rejuvenation attracted support from various social classes and consolidated power under leaders like Mussolini and Hitler, who vowed to restore national pride and order amidst economic and political instability.
While some aspects of fascism were shared with authoritarian and communist regimes, including the consolidation of power and control over individuals' lives, the fascist commitment to nationalism and racial ideologies set it apart. Its totalitarian nature led to the suppression of opposition, rigorous control of industry and commerce, and glorification of the state, often embodied in a single authoritarian leader. Their ideologies, though rooted in different philosophical underpinnings, shared the common feature of imposing strict governmental control and limiting personal freedoms in exchange for promises of stability and prosperity.