A call option on GMSS stock with a strike price of $20 and an expiration date 9 months from now is worth $2 today. A put option on GMSS stock with a strike price of $20 and an expiration date 9 months from now is worth $5.58 today. The risk-free rate of return is 4%, and the stock pays no dividends. According to put-call parity, the GMSS stock should be worth ____ today. (Use continuous compounding interest rate)?

a) $15.71 b) $15.98 c) $16.38 d) $33.98 e) None of the above