21.4. Use Black’s model to value a 1-year European put option on a 10-year bond. The current cash price of the bond is $125, the strike price is $110, the 1-year risk-free interest rate is 10% per annum, the bond’s forward price volatility is 8% per annum, and the present value of the coupons that will be paid during the life of the option is $10.