An Option to Purchase Clause is a term in a contract that gives one party the right to buy an asset or property at a predetermined price within a certain time frame. This clause is typically found in leases and other real estate contracts. The party that has the option is said to have the optioned, and the party granting the option is said to be the option or. There are two types of Option to Purchase Clauses: call options and put options. A call option gives the optioned the right to buy the asset or property at the predetermined price, while a put option gives the optioned the right to sell the asset or property at the predetermined price.