Which of the following defines a contract?

A contract is a legally binding agreement that typically consists of three essential elements: offer, acceptance, and consideration. The "offer" is a proposal made by one party to enter into an agreement, while "acceptance" is the agreement by the other party to the proposed terms. "Consideration" refers to something of value that is exchanged between the parties, which can be goods, services, or a promise to act or refrain from acting in a certain way. These three components form the foundation of a valid contract, establishing mutual responsibilities between the involved parties.

In contrast, while the other options incorporate some of these elements, they do not include all three as defined by the essential characteristics of a contract. This lack of completeness in the other choices makes them insufficient to define a contract accurately.