When buying or selling options, the investor or trader has the right to exercise that option at any point up until the expiration date - so simply buying or selling an option doesn't mean you actually have to exercise it at the buy/sell point. Because of this system, options are considered derivative securities - which means their price is derived from something else (in this case, from the value of assets like the market, securities or other underlying instruments). For this reason, options are often considered less risky than stocks (if used correctly). 
For example: A steel manufacturer importing coal from Australia currently and in order to reduce the volatility of changes in prices he always hedges the coal purchases on a 3 monthly forward contract where he agrees with the seller on day one of financial quarter to supply coal at defined price irrespective of price movements during quarter. So in this case, the contract is forward/future and buyer has an intention to buy the goods and no intention of making profit from price changes.
An option's price, its premium, tracks the price of its underlying futures contract which, in turn, tracks the price of the underlying cash. Therefore, the March T-bond option premium tracks the March T-bond futures price. The December S&P 500 index option follows the December S&P 500 index futures. The May soybean option tracks the May soybean futures contract. Because option prices track futures prices, speculators can use them to take advantage of price changes in the underlying commodity, and hedgers can protect their cash positions with them. Speculators can take outright positions in options. Options can also be used in hedging strategies with futures and cash positions.
A long options trade is entered by buying an options contract and paying the premium to the options seller. If the market then moves in the desired direction, the options contract will come into profit (in the money). There are two different ways that an in the money option can be turned into realized profit. The first is to sell the contract (as with futures contracts) and keep the difference between the buying and selling prices as the profit. Selling an options contract to exit a long trade is safe because the sale is of an already owned contract.
An option is a contract that allows (but doesn't require) an investor to buy or sell an underlying instrument like a security, ETF or even index at a predetermined price over a certain period of time. Buying and selling options is done on the options market, which trades contracts based on securities. Buying an option that allows you to buy shares at a later time is called a "call option," whereas buying an option that allows you to sell shares at a later time is called a "put option."