5. A European put with a 9-month expiry and a strike of $20 costs $3. The underlying stock price is $21, and a dividend of $0.7 is expected in 6 months. Risk-free interest rates are 3% for all maturities. (a) What is the price of a European call option with a 9-month expiry and a strike of $20? (b) Explain the arbitrage strategy and profit if the European call price is $4.