Final answer:
President Warren G. Harding's election in 1920 was characterized by a promise of social conservatism, prosperity and normalcy, marking the beginning of the Jazz Age.
Step-by-step explanation:
With his election in 1920, President Warren G. Harding promised a return to what Americans longed for after World War I and the Progressive era—an era of personal freedom, low taxes, limited government intervention, and focusing on business without the entanglements of international affairs. This time became known as the Jazz Age, during which Americans looked forward to prosperity and normalcy. Harding won the presidency with an overwhelming majority, marking a clear choice for social and economic policies that were less about government intervention and more about personal enjoyment and business growth. Hence, among the options listed, Harding's election promised a period marked by C) Social conservatism.