First's current stock price is $260. The price may rise to $300 or fall to $170 in one month. The risk-free interest rate is 18% per year.
a. Using the replication portfolio approach, determine the price of a call on First's stock with an exercise price of $280 and one month maturity.
b. Using the risk neutral approach, determine the price of a put on First's stock with an exercise price of $280 and one month maturity.
c. If the call option in part (a) is selling at $12, show how you can make arbitrage profit.