A person selling or leasing residential housing may not discriminate based solely by race as a result of:

The correct answer highlights the fundamental principles established by the Civil Rights Act of 1866, which is a significant piece of legislation in the context of housing discrimination. This Act unequivocally prohibits discrimination based on race in the context of property ownership, which means that no person can be excluded from the right to sell or lease residential housing solely based on their race.

The importance of this Act lies in its establishment of equal rights for all citizens in property transactions, serving as the legal foundation that supports anti-discrimination laws in real estate to this day. The Act was one of the first pieces of legislation aimed directly at safeguarding civil rights after the Civil War and it continues to have a lasting impact on housing laws in the United States.

In contrast, while the other options listed do address housing discrimination and provide protections, they do so within a broader context or expand upon the original principles laid down by earlier legislation, rather than establishing the initial prohibition against race-based discrimination.