At the annual effective rate of 4%, the present value of a series of 7 payments is $ 94.15. The Macaulay duration of this series of payments is 12.65.

If you buy this series of payments and also buy, at 4% annual effective rate, a 5-year coupon-free bond with a face value of $ 100, determine the Macauley duration of those 8 payments.

a. 8.83

b. 8.57

c. 10.33

d. 9.56

e. 9.08