A mortgage of $169,900 was taken out when the 5-year mortgage interest rate was 7.2% compounded semi-annually. 36 months later, the 5-year mortgage interest rate has decreased to 5.5%. What would be the new blend-and-extend mortgage rate if this mortgage is refinanced for a new 5-year term? Select one: a. 7.20% b. 6.18% c. 5.50% d. 6.34% e. 6.80%