Which of the following is considered unsecured debt?

Unsecured debt refers to loans that are not backed by any physical asset or collateral. In this context, credit cards that rely solely on the borrower's creditworthiness exemplify unsecured debt because they are extended based on the borrower's promise to repay, without any specific asset pledged to guarantee payment. If the borrower defaults, the lender does not have a right to any specific property as security.

In contrast, mortgages on a house, car loans with collateral, and home equity loans are all secured debts. These types of loans require collateral—such as the house in the case of a mortgage or the car for an auto loan—which the lender can seize if the borrower fails to make payments. This collateral backing provides the lender with a level of security that is absent with unsecured debt. Therefore, the classification of credit cards as unsecured debt is accurate, as they depend entirely on the borrower's credit history and ability to repay without any physical asset serving as security.