Which statement about a conventional mortgage loan is true?

A conventional mortgage loan is defined as one that typically does not require mortgage default insurance. If the borrower makes a down payment of 20% or more of the home's purchase price, the lender does not mandate that the borrower obtain mortgage insurance, which protects the lender in case of borrower default. This means that when the down payment reaches or exceeds 20%, the loan is considered "conventional," and the borrower benefits from lower overall costs because they can avoid the added expense of mortgage insurance.

The other statements do not accurately represent conventional mortgage loans. While some conventional loans may have fixed interest rates, they can also be offered with variable rates, so this does not hold true universally. Additionally, conventional loans are not exclusive to first-time homebuyers; they are available to any eligible borrower with the financial means to obtain the loan, regardless of their purchasing history. Lastly, conventional loans do not require insurance for smaller down payments (less than 20%), which would imply that insurance is mandatory for all conventional loans, which is not the case.