Please help I need it now What was a major factor that caused the Great Depression?

1. a decline in crop production by American farmers
2.high wages paid by employers
3.increases in the tax rate for corporations
4.speculators borrowed money to buy shares of stocks

4. Speculators borrowed money to buy shares of stocks

Explanation:

A big problem in 1929 was that investors borrowed too much money to invest in the stock market, believing that the stock market would keep on rising and never decline. ... When the market did decline, creditors wanted their money back, but financially ailing investors were over-leveraged, and couldn't repay their loans.

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climate change is the big reason to the decline of the indus valley which also caused floods. so i dont know what answer would best fit the description thats just what i found online! have an awesome