If the option expired unexercised, then it is referred to as abandoned. Options are used for risk management, investing, and speculative purposes. Options are also used by some individuals for hedging portfolios or for speculative purposes. There are various issues relating to suitability for options. Options are available for many products and derivatives.
Options are flexible trading and risk management tools.
There are many options pricing models. However, it should be remembered that whatever the model chosen and the level of complexity all these models should produce the same result at the end or expiry. If not, then there is a bias which may be exploitable in an arbitrage sense. Finally, it should be noted that options models as well as other financial evaluation packages and software should come with a warning. For more information, this online site contains many references for Options and other Derivatives.