Use the Black-Scholes formula to value the following options:
a. A call option written on a stock selling for $60 per share with a $60 exercise price. The stock's standard deviation is 6% per month. The option matures in three months and the risk-free rate is 1% per month.
b. A put option written on the same stock as described in (a) above, at the same time, with the same stock price, exercise price, risk-free rate, and expiration date.