(10 points) (a) Use the Black-Scholes option pricing formula to calculate the price of a European put option on a stock when the stock price is $69, the strike price is $70, the risk-free interest rate is 5% per annum, the volatility is 35% per annum, and the time to maturity is six months. (b) Show that the Black-Scholes option pricing formulas for call and put options satisfy the put-call parity, i.e., show that c+ Ke=T = p+S(0) where c and p are the prices of call and put options, respectively