Under the Fair Housing Act, which of the following is a protected class when it comes to residential mortgage lending?

Correct answer: National origin

The Fair Housing Act prohibits discrimination in residential real estate transactions based on race, color, national origin, religion, sex, familial status, and disability. National origin is explicitly one of these protected classes. Credit score, employment status, and debt-to-income ratio are legitimate underwriting criteria that lenders may use to evaluate creditworthiness and are not protected characteristics under the Fair Housing Act.