The right answer is:
A: The stock market crash caused a panic > people rushed to pull money out of the banks > Banks did not have enough money for everyone.
Explanation
The aforementioned excerpt is from "American Life Histories: Manuscripts from the Federal Writers' Project, 1936-1940" and it describes a group of men in New York City who made a living by collecting and selling junk from their pushcarts.
It specifically refers to the stock market crash of 1929 during which there was a collapse of stock prices. It was the worst decline in U.S. history.
People were forced to sell businesses and take out their life savings. Unemployment took place later as businesses failed.