Which of the following was a cause of the Great Depression during Franklin Roosevelt's presidency?

The stock market crash was a pivotal cause of the Great Depression during Franklin Roosevelt's presidency. This catastrophic event occurred in late October 1929 and marked the beginning of a decade-long economic downturn. The crash significantly eroded public confidence in the financial system and led to widespread bank failures, business bankruptcies, and massive unemployment.

When the stock market collapsed, it triggered a chain reaction. Businesses suffered as investors pulled out their money, leading to decreased spending and production, which resulted in layoffs and further reductions in consumer spending. This cycle of decline only deepened the economic crisis. The stock market crash highlighted the vulnerabilities in the financial sector and contributed to the economic turmoil that defined the Great Depression, necessitating the extensive reforms and recovery measures implemented by Roosevelt's New Deal programs.

The other options represent conditions that, while significant in their own right, did not catalyze the Great Depression in the same way the stock market crash did. High employment rates, for instance, would indicate a flourishing economy, directly contradicting the reality of the Great Depression. Similarly, the expansion of production and increased trade agreements were not factors that initiated the economic collapse; rather, they came about as responses to the economic conditions faced during that period.