11. A European call option and put option on a stock both have a strike price of $20 and an expiration date in 3 months. The put option sells for $3. The risk-free interest rate is 10% per annum, and the current stock price is $19.

a) What should the price of the call option be given the information above?

b) Identify the arbitrage opportunity open to a trader and describe the trading strategy if the call option is also priced at $3.