Which of the following is classified as a protected characteristic under federal law?

Marital status is classified as a protected characteristic under federal law, specifically in the context of housing and mortgage-related practices. The Fair Housing Act, which is a critical piece of legislation in the realm of housing discrimination, prohibits discrimination based on various protected characteristics. These include race, color, national origin, religion, sex, familial status, and disability. While marital status is not explicitly listed in the Fair Housing Act, it is often included in broader interpretations by various states and local ordinances that also align with federal guidelines, particularly concerning housing availability and rights.

Other options, such as income level, education attainment, and employment history, do not have the same level of protection under federal laws. For example, while these factors can influence lending decisions and be indicators of creditworthiness, they do not encompass the same scope of protected characteristics aimed at preventing discrimination based on personal attributes that can significantly affect individuals' access to housing and equal treatment under the law.