If in six months the market crashes by 20% (500 points on the index), he or she has made 250 points by being able to sell the index at $2250 when it is trading at $2000—a combined loss of just 10%. In fact, even if the market drops to zero, the loss would only be 10% if this put option is held. Again, purchasing the option will carry a cost (the premium), and if the market doesn’t drop during that period, the maximum loss on the option is just the premium spent.
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.
Because options prices can be modeled mathematically with a model such as the Black-Scholes, many of the risks associated with options can also be modeled and understood. This particular feature of options actually makes them arguably less risky than other asset classes, or at least allows the risks associated with options to be understood and evaluated. Individual risks have been assigned Greek letter names, and are sometimes referred to simply as "the Greeks."
Conversely, a put option is a contract that gives the investor the right to sell a certain amount of shares (again, typically 100 per contract) of a certain security or commodity at a specified price over a certain amount of time. Just like call options, a put option allows the trader the right (but not obligation) to sell a security by the contract's expiration date.
However, for put options (right to sell), the opposite is true - with strike prices below the current share price being considered "out of the money" and vice versa. And, what's more important - any "out of the money" options (whether call or put options) are worthless at expiration (so you really want to have an "in the money" option when trading on the stock market).
The purchase of a call option is a long position, a bet that the underlying futures price will move higher. For example, if one expects corn futures to move higher, they might buy a corn call option. The purchase of a put option is a short position, a bet that the underlying futures price will move lower. For example, if one expects soybean futures to move lower, they might buy a soybean put option.
So, call options are also much like insurance - you are paying for a contract that expires at a set time but allows you to purchase a security (like a stock) at a predetermined price (which won't go up even if the price of the stock on the market does). However, you will have to renew your option (typically on a weekly, monthly or quarterly basis). For this reason, options are always experiencing what's called time decay - meaning their value decays over time.