Bonds : Academic approach

Several years ago, Durham City issued $1 million in zero coupon bonds due and payable in 2010. The bonds were sold at an amount to yield investors 6% over the life of the bonds. During the current year, how much interest expenditures would Durham City recognize related to these bonds?

a) Difference between the present value of the bonds at the beginning of the period and the present value of the bonds at the end of the period.
b) Face amounts of bonds times 6%.
c) Book value of bonds times 6%.
d) None