Options on stocks have been traded since 1973, with markets growing in volume and variety. These options can be traded on different exchanges worldwide, covering assets like stocks, currencies, and commodities. There are two main types of options: call options allow buying at a set price and date, while put options allow selling. The price is called the strike price, and the date is the expiration date. Options can be European (exercisable only on expiration) or American (exercisable anytime before expiration). Most options traded are American.