The bank issued a $171,000 25-year mortgage (monthly payments) with an annual interest rate of 9.70%. They just received payment number 106 and have decided to sell the loan. The buyer of the loan expects to receive an annual rate of return equal to 11.70%. For the original bank that issued the loan, what was the internal rate of return?

a. 10.83% b. 7.39% c. 8.95% d. 9.84% e. 8.13%