A stock price is currently $$40.$ It is known that at the end of three months it will

be either $$44$ or $$36.$ The risk$-$free rate of interest with continuous compounding

is $8\%$ per annum. Calculate the value of a three$-$month European call option

on the stock with an exercise price of $$39.$ Verify that no$-$arbitrage arguments

and risk$-$neutral valuation arguments give the same answers.