The characteristics of a fixed-rate mortgage include a:

A fixed-rate mortgage is characterized by a fixed interest rate that remains constant throughout the life of the loan, ensuring that the borrower’s monthly principal and interest payments remain the same over time. This is the defining feature of a fixed-rate mortgage.

Other options:

A fixed margin (A) applies to adjustable-rate mortgages (ARMs).

Mandatory 30-year terms (C) and balloon payments (D) are not characteristics of a fixed-rate mortgage, as fixed-rate loans can have varying term lengths (15, 20, or 30 years) without balloon payments.

References:

Fannie Mae Selling Guide on fixed-rate mortgages

Freddie Mac Mortgage Products