Answer:
D. falling crop prices
Explanation:
The biggest factor that led to the Great Depression was the big drop in the crop prices. The reason why this happened was the bad planning of the agricultural sector and farmers. They managed to produce much more crops then what the domestic market demanded, but also more then what was demanded for export. This led to enormous surplus of crops, so the prices started to drop incredibly low. This created a chain reaction, so the whole economy started to crumble because of it, and in accordance to it, the national currency as well, leading to big inflation.
