be the exercise price and
the price of the underlying stock at the maturity date.
The payoff of a call option is:
> K, then the call is said to expire in-the-money and the option holder can exercise the right to buy the underlying asset at price K rather than at the current market price
The payoff of a put option is:
< K, then the put is said to expire in-the-money and the option will be exercised.