Final answer:
In the 1920s before the Great Depression, American Presidents supported laissez-faire economics, but policies shifted towards government intervention with FDR's New Deal after the 1929 crash.
Step-by-step explanation:
During the economic slump of the 1920s leading up to the Great Depression, American Presidents primarily supported c) Laissez-faire economics. This hands-off approach was predominant until the onset of the Great Depression. After the stock market crash of 1929, President Herbert Hoover, despite being commonly thought of as a laissez-faire advocate, actually implemented interventions such as tax cuts and the creation of the Reconstruction Finance Corporation (RFC) in efforts to combat the economic downturn. However, it was not until President Franklin D. Roosevelt's election and his subsequent New Deal policies that government intervention became a centerpiece of American economic policy. The New Deal programs expanded government regulation, introduced social welfare programs, and marked a shift away from laissez-faire economics.