When buying a call option, the strike price of an option for a stock, for example, will be determined based on the current price of that stock. For example, if a share of a given stock (like Amazon (AMZN) ) is $1,748, any strike price (price of the call option) that is above that share price is considered to be "out of the money." Conversely, if the strike price is under the current share price of the stock, it's considered "in the money." 
For example, a plastics producer could use commodity futures to lock in a price for buying natural gas by-products needed for production at a date in the future. The price of natural gas—like all petroleum products—can fluctuate considerably, and since the producer requires the natural gas by-product for production, they are at risk of cost increases in the future.
Traders that are willing to accept considerable amounts of risk with the prospects of limited reward, can write (or sell) options, collecting the premium and taking advantage of the well-known belief that more options than not expire worthless. The premium collected by a commodity option seller is seen as a liability until the option is either offset (by buying it back), or it expires. This is because as long as the option position is open (the trader is short the commodity option), there is substantial risk exposure. Should the futures price trade beyond the strike price of the option, the risk is similar to holding a commodity futures contract outright.
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."