Option Contract
This is a type of contract that protects an investor from the seller’s ability to revoke the contract before an agreed upon time for a specified amount.
An example of such an option is an investor (an offeree) who agrees to buy a certain number of stocks at an agreed upon price by the end of the business day from a seller (offeror). The offeror of the stock gives up their ability to revoke the contract until or unless the investor imposes or revokes the option.