The right to trade an investment over a period of time is called an option. It is the privilege sold by one party to another that offers the buyer to buy or sell a security over an agreed price in a specific period of time. There are actually two types of options, the calls and the puts. A call gives right to a holder to buy an asset in an agreed price over a period of time while a put gives the holder a right to sell an asset for a price over a period of time.