15. The Black-Scholes-Merton option pricing model assumes the stock price changes are lognormally distributed. Show graphically how this distribution changes when an investor is long the stock and short the call. For problems 16, 17, and 18, determine the profit from the following basic foreign currency option transactions for each of the following spot rates at expiration: $0.90, $0.95, $1.00, $1.05, and $1.10. Construct a profit graph. Find the breakeven spot rate at expiration. Assume that each contract covers 100,000 Euros.