Which of the following is an example of a unilateral contract?

A unilateral contract is a type of agreement where one party makes a promise or assumes an obligation while the other party is not required to take any action in return. In this context, the correct answer—an option—fits this definition perfectly. An option in real estate gives one party the right to buy or sell a property within a specified time frame, but it does not obligate them to do so. The seller, however, is bound to uphold the agreement if the buyer chooses to exercise the option within that time frame.

The other options represent contracts that involve mutual obligations. A lease, for instance, involves both the landlord and tenant agreeing to specific terms where both parties have responsibilities. Similarly, an accepted offer indicates that both parties have consented to the terms of a contract, thereby creating mutual obligations. A purchase and sale agreement also establishes obligations for both the buyer and seller. In contrast, since the option only binds one party to the terms while allowing the other party the choice to act or not, it is a clear example of a unilateral contract.