Which scenario is legal in terms of real estate practices?

The scenario where homes are shown only in a neighborhood with a high Russian population to a Russian client is legal as it reflects the practice of steering clients towards areas where they might feel more comfortable or accepted due to cultural similarities. This practice can also align with the client's preferences, as they may be interested in communities with shared cultural values.

It's important to note, however, that while this practice can sometimes be seen as client-oriented, it can raise questions about fair housing practices if it leads to exclusionary effects or reinforces racial or ethnic segregation. Therefore, while it's legal in this context, real estate professionals should always be cautious and ensure that they are acting in accordance with fair housing laws and promoting equal opportunities for all clients.

In contrast, other scenarios listed involve discriminatory practices that are prohibited under fair housing laws, such as refusing service to individuals based on gender or relying on nationality to impose extra charges. Additionally, not accommodating service animals violates regulations that protect individuals with disabilities.