27. Rates for adjustable-rate mortgages are commonly tied to the a. average prime rate over the previous year. b. Fed's discount rate over the previous year. c. average Treasury bill rate over the previous year, d. average Treasury bond rate over the previous year. 28. From the perspective of the lending financial institution, interest rate risk is a lower on a 30-year fixed-rate mortgage than on a 15-year fixed-rate mortgage b. lower on a 15-year fixed-rate mortgage than on a 30-year fixed-rate mortgage c. higher on a 15-year fixed-rate mortgage than on a 30-year fixed-rate mortgage d. higher on a 15-year adjustable-rate mortgage than on a 30-year adjustable rate mortgage