The correct answer to this question is the following.
Although there are no options attached we can say the following.
The "great bull market" is an economic term that refers to a situation lived in the market or a specific condition of the market in which prices are rising. That was the case of the US stock market before its crash on October 29, 1929. This crash represented the beginning of the Great Depression.
The main causes of the United States Great Depression were the following.
During the 1920s, the American people were living a period of economic prosperity known as the "Roaring 1920s." During this period, people buy all kinds of things, needed or not. They bought houses, cars, electro domestics, and more. However, most of these purchases were made on credit, generating a big debt. Another cause was the overproduction of goods. Then, the inaction on the part of the federal government to prevent or regulate these conditions.
The major cause that detonated the Great Depression was the United States Stock market crash of October 29, 1929. After this crash millions of Americans lost their jobs, banks declared bankruptcy, and thousands of companies broke.