Trickle Corporation's 12 percent coupon rate, semiannual payment, $1,000 par value bonds mature in 25 years. The bonds currently sell for $1,230.51 in the market, and the yield curve is flat Assuming that the yield curve is expected to remain flat, what is Trickle's most likely before-tax cost of debt if it issues new bonds today? Select one: O a. 4.78% O b. 6.46% O c. 7.70% O d. 9.56% O e. 12.92%