What must a buyer do when borrowing money for a down payment?

When a buyer borrows money for a down payment, the requirement to pay it back with interest is essential because borrowing money inherently involves a repayment obligation. Lenders provide funds to borrowers with the expectation that they will repay the principal amount along with any interest that accrues over the period of the loan. This interest serves as the lender's compensation for the risk and opportunity cost of providing the funds.

The other options do not accurately reflect the requirements or protocols involved in borrowing money for a down payment. Securing it with collateral is not a standard practice for down payments specifically, as most real estate transactions do not require collateral beyond the property itself. Making no further payments contradicts the very nature of borrowing, as borrowed funds must be repaid. Similarly, subleasing the property is unrelated to the borrowing process and does not pertain to the obligations of the buyer regarding their down payment.