A price of an asset is currently S$0.$ At the end of T months it will be either

S$0$u or S$0$d$.$ The risk$-$free rate of interest with continuous compounding

is r$\%$ per annum. Find the $$ used for risk$-$free portfolio. Calculate the

value of a T$-$month European call and put options on the stock with strike

price of $K