Adjustable-Rate Mortgage. Discuss the characteristics of an adjustable-rate mortgage. What influences your choice of a fixed- or adjustable-rate mortgage? The interest rate on adjustable-rate mortgages: (Select the best answer below.) O A. dictates how the payment is split between principal and interest. B. must specify the frequency with which the mortgage payment is made. O C. changes according to an interest rate on fixed-rate mortgages. OD. changes according to an interest rate index