Which of the following terms is synonymous with seller financing that includes existing mortgage retention?

A wrap-around mortgage is a type of seller financing that allows the seller to retain the existing mortgage while also providing financing to the buyer. In this arrangement, the buyer makes payments to the seller, who in turn continues to make payments on the original mortgage. This is beneficial for the seller because it allows them to potentially receive higher interest payments while not having to pay off the original mortgage immediately. Additionally, the buyer benefits from the possibility of obtaining a loan when they might not otherwise qualify for a traditional mortgage, often with terms that are more favorable.

Conventional mortgages, interest-only mortgages, and fixed-rate mortgages do not relate to the concept of seller financing with existing mortgage retention. These terms describe standard forms of mortgages that involve direct lending from a financial institution rather than a seller-to-buyer transaction involving the retention of an existing mortgage. Therefore, the wrap-around mortgage is the only option that fits the description provided in the question.