Trickle Corporation's 12 Percent Coupon Rate,semiannual Payment,$1,000 Par Value Bonds

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?

A) 4.78%
B) 6.46%
C) 7.70%
D) 9.56%
E) 12.92%