Which action by a lender would be considered discriminatory?

Charging a higher interest rate solely because the buyer is single is considered discriminatory because it violates fair lending laws, which prohibit discrimination based on marital status among other protected characteristics. The Fair Housing Act and the Equal Credit Opportunity Act aim to ensure that lenders provide equitable access to credit, regardless of personal characteristics unrelated to creditworthiness, such as being single, married, or part of any other demographic group.

In the context of lending practices, factors such as credit history, income, and the ability to pay back the loan are legitimate criteria for determining loan terms, but an individual's marital status does not correspond to their ability to repay a loan. This makes it problematic to base lending decisions on such characteristics.

Other options presented involve considerations that may be more directly related to the borrower’s financial situation, such as creditworthiness or the standard terms of lending that apply to any borrower. These do not inherently reflect discrimination based on protected personal attributes.