What did severe drought stock speculation and banking crises lead to?

Severe drought, stock speculation, and a banking crisis in the late 1920s lead to the Great Depression. The Great Depression was a severe global economic depression which began in the United States. It started after the stock market crash of October 1929 and lasted until about 1939.

the graph shows the spread of railways in the 1800s.

based on the graph, the conclusion that can be drawn about germany is answer d)   by 1880, germany had more rail lines than great britain and russia.