Question

in the 1920s, the danger of buying stock on credit was that if the stock dropped, borrowers
could not repay loans used
to buy the stock.
lost ownership of the stock.
could no longer speculate
on stock.
could no longer get credit.

Explanation:

Buying stock on credit (margin buying) in the 1920s meant borrowers used loans to purchase stocks. If the stock price dropped, the value of the stock (collateral) fell below the loan amount. Borrowers then couldn’t repay the loan used to buy the stock, as the stock’s value no longer covered the debt. Other options: losing ownership isn’t the direct danger of credit - related repayment; speculation or getting credit aren’t the primary dangers here.

Answer:

could not repay loans used to buy the stock.