Which is NOT considered a protected class under fair housing laws?

In the context of fair housing laws, income is not considered a protected class. Protected classes typically include categories such as race, religion, color, national origin, sex, familial status, and disability, as established by the Fair Housing Act. These laws are designed to prevent discrimination against individuals based on these characteristics in housing-related activities.

Income, while an important factor in housing and lending decisions, does not fall under the same legal protections. Individuals can be treated differently based on their income levels, which could affect their access to housing, but this is not classified as discrimination under federal fair housing laws. Therefore, income stands out as the correct answer in the context of this question.