Question $4(20$ pts$).$ A trader buys $($long$)$ a call option with a strike price of $$120$ and

sells $($short$)$ a put option with a strike price of $$100.$ Both options have the same maturity.

The call costs $$20$ and the price of put is $$10.$ What is the portfolio payoff at expiry if

the security price at expiry is $$70?$ Draw a diagram showing the variation of the trader's

profit with the security price at expiry.