4. (10 points) Suppose today at time 0 the price of a (European) put option written on a stock with strike price K=$50 and maturity T is P0(K,T)=$5. The current spot price of the stock is S0=$40. Show that buying the put and buying one share today on margin (which means that the required money for the purchase is borrowed and has to be paid back at maturity T ) constitues an arbitrage opportunity. For simplicity, assume that money can be borrowed at an interest rate of zero. Hint: Provide a table similar to the one discussed in class and during the discussion session