Final answer:
The financial practice that most likely contributed to the Great Depression was banks lending money for investments and investing in the stock market using their depositors' money.
Step-by-step explanation:
The correct financial practice that most likely contributed to the Great Depression was option B: Banks lent money for investments and invested in the stock market using their depositors' money. This practice, known as speculation, led to a stock market bubble and eventually a crash in 1929. Many banks had invested heavily in the stock market, and when the market crashed, they lost a significant amount of money, causing widespread bank failures and contributing to the severity of the economic downturn.
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