You purchase a new car for $16,000 and decide to borrow the entire $16,000. Your loan is for 4 years with an annual interest rate of 9% compounded monthly. You will make monthly payments on the loan. What number below is closest to the total interest (not principle) you have paid after 6 months of payments?

a) $641.22

b) $688.39

c) $712.43

d) $762.90

e) $798.05

f) $822.66