What is a unilateral contract?

A unilateral contract is defined as a type of contract in which one party makes a promise in exchange for the performance of an act by another party. In this arrangement, only one party, the offeror, is obligated to fulfill their promise once the offeree completes the specified act. For example, if someone offers a reward for finding a lost pet, the person who claims that reward does not promise to find the pet but instead performs the act of finding it. Once that act is completed, the offeror is legally bound to fulfill their promise of payment.

This understanding distinguishes unilateral contracts from bilateral contracts, where both parties engage in mutual promises, creating obligations for both sides. The other options illustrate scenarios that do not align with the definition of a unilateral contract.