Shrike Services has 9.25 percent coupon bonds outstanding with a current market price of $987.43. The yield to maturity is 9.50 percent and the face value is $1,000. Interest is paid semiannually. How many years is it until these bonds mature?

a. 7 years

b. 9 years

c. 11 years

d. 13 years

e. 15 years

Which one of these is correct?