What major event marked the United States' full emergence from the Great Depression?

The bombing of Pearl Harbor in December 1941 is considered a significant event that marked the United States' full emergence from the Great Depression, as it led to the country's entry into World War II. The war effort created a massive demand for industrial production, which in turn stimulated economic growth and reduced unemployment rates. Factories that had been idle due to the economic downturn shifted to wartime production, leading to significant job creation and revitalization of the economy.

This contrast starkly with the other options. The signing of the New Deal refers to a series of programs and reforms introduced in the 1930s by Franklin D. Roosevelt aimed at providing relief and recovery during the Great Depression, but it did not mark the end of the economic crisis. The enactment of the Marshall Plan occurred after World War II, aimed at rebuilding Europe rather than addressing the Great Depression. The election of Franklin D. Roosevelt marked the beginning of efforts to combat the Great Depression but did not represent the end of it. Therefore, Pearl Harbor represents the turning point that shifted the U.S. economy into a wartime footing, ultimately leading to recovery from the Depression.