Final answer:
The student's issue with declining European sales relates to the high tariffs imposed by the Hawley-Smoot Tariff Act, which stifled international trade and contributed to the broader economic downturn of the Great Depression.
Step-by-step explanation:
The quote "I used to be able to sell my goods to the Europeans. It was great having more customers! Now the Europeans won't buy any and I'm making a lot less money!" best aligns with the cause of the Great Depression related to high tariffs. The issue described in the quote refers to the Hawley-Smoot Tariff Act of 1930, which was intended to protect American businesses from foreign competition but ultimately led to other countries imposing their own tariffs. As a result, international trade was significantly reduced, contributing to economic decline both in the U.S. and abroad.
This trade barrier not only impacted foreign sales for American producers but also exacerbated the underlying problems of overproduction and unequal distribution of income, as these producers found their domestic markets oversaturated and a vast majority of consumers unable to afford their goods due to income disparities.
John Maynard Keynes, in his work 'The General Theory of Employment, Interest, and Money,' emphasized that the lack of aggregate demand was a fundamental issue during the Great Depression, further supporting the argument that high tariffs contributed to shrinking markets and reduced sales.