The price of a non-dividend-paying stock is $19 and the price of a 3-month European call option on the stock with a strike price of $20 is $1. The risk-free rate is 4% per annum. The price of a 3-month European put option (P) with a strike price of $20 is $1.80.
a) Find the arbitrage profit and describe the arbitrage scheme if the put option price (P) = $1.70.
b) Find the arbitrage profit and describe the arbitrage scheme if the put option price (P) = $1.90.