Market expectations of commodity due to variations in demand and supply (If the market feels commodity may go up and traders are bullish about commodity, then forward prices are higher than forward parity price, whereas, if market feels that prices may go down then forward prices may be lesser) The expectations  are mainly dependent on demand supply factoINR.
In case of futures, a buyer of a contract is said to be “long position holder” and a seller is “Short position holder”. In the case of futures, to avoid the risk of defaulting contract involves both parties lodging a certain percentage margin of value of contract with a mutually trusted third party. Generally, in gold futures trading, margin varies between 2%-20% depending on the volatility of gold in spot market.

Of course, many investors, especially new investors, are skittish about options. After all, no investor is required to trade this way, and the transactions can seem complicated. But once you know the pros and cons of this type of investing, it can be a powerful part of your strategy. No investors should be sitting on the sidelines simply because they don’t understand options.
Options are powerful because they can enhance an individual’s portfolio. They do this through added income, protection, and even leverage. Depending on the situation, there is usually an option scenario appropriate for an investor’s goal. A popular example would be using options as an effective hedge against a declining stock market to limit downside losses. Options can also be used to generate recurring income. Additionally, they are often used for speculative purposes such as wagering on the direction of a stock.
Call writers and put writers (sellers), however, are obligated to buy or sell if the option expires in-the-money (more on that below). This means that a seller may be required to make good on a promise to buy or sell. It also implies that option sellers have exposure to more, and in some cases, unlimited, risks. This means writers can lose much more than the price of the options premium.
Covered calls can make you money when the stock price increases or stays pretty constant over the time of the option contract. However, you could lose money with this kind of trade if the stock price falls too much (but can actually still make money if it only falls a little bit). But by using this strategy, you are actually protecting your investment from decreases in share price while giving yourself the opportunity to make money while the stock price is flat. 
Commodity futures used by companies give a hedge to the risk of adverse price movements. The goal of hedging is to prevent losses from potentially unfavorable price changes rather than to speculate. Many companies that hedge use or producing the underlying asset of a futures contract. Examples of commodities hedging use include farmers, oil producers, livestock breeders, manufacturers, and many others.
With straddles (long in this example), you as a trader are expecting the asset (like a stock) to be highly volatile, but don't know the direction in which it will go (up or down). When using a straddle strategy, you as the trader are buying a call and put option at the same strike price, underlying price and expiry date. This strategy is often used when a trader is expecting the stock of a particular company to plummet or skyrocket, usually following an event like an earnings report. For example, when a company like Apple  (AAPL) is getting ready to release their third quarter earnings on July 31st, an options trader could use a straddle strategy to buy a call option to expire on that date at the current Apple stock price, and also buy a put option to expire on the same day for the same price.

Just as there are several ways to skin a cat, there are an unlimited number of option trading strategies available in the futures markets. The method that you choose should be based on your personality, risk capital and risk aversion. Plainly, if you don't have an aggressive personality and a high tolerance for pain, you probably shouldn't be employing a futures and options trading strategy that involves elevated risks. Doing so will often results in panic liquidation of trades at inopportune times as well as other unsound emotional decisions.
The fee you are paying to buy the call option is called the premium (it's essentially the cost of buying the contract which will allow you to eventually buy the stock or security). In this sense, the premium of the call option is sort of like a down-payment like you would place on a house or car. When purchasing a call option, you agree with the seller on a strike price and are given the option to buy the security at a predetermined price (which doesn't change until the contract expires).