A real estate option is a unilateral contract. The optionor grants to the buyer/optionee the right to purchase the property for the agreed price by an agreed date. Consideration is required. The optionee may close on the property or not. If he does not close he forfeits his option consideration. The consideration can be money or a lease is determined to be consideration. The amount of consideration should not be a frivolous amount like one dollar or $10.
The strike price must be stated in the agreement or determined by a formula.
There must be an end date. Any of these terms can be renegotiated during the option term but they cannot be unilaterally changed by the optionor.
The buyer may sell or assign his option rights to another party to close on the same terms. Contracts are assignable unless they specifically state they are not assignable. The option grants a title right in the property.