ABC Company has $40 million face value outstanding of zero coupon bonds that mature in three years. The current market value of the firm's assets is $43 million, with a standard deviation of 35% per year. If the risk-free rate is 8% per year compounded continuously, what is the firm's continuously-compounded cost of debt? Select one: a. 10.36% b. 12.78% c. 13.40% d. 15.24% e. 17.67%