Which of the following describes a contract?

A contract is characterized as a mutually binding legal relationship between at least two parties, where each party involves an agreement to fulfill specific obligations, rights, and responsibilities. This definition encompasses key elements such as an offer, acceptance, consideration, and the capacity of parties to enter into the contractual agreement. The binding nature means that the law provides recourse in the event one party fails to uphold their end of the agreement.

In contrast, an informal agreement between parties lacks the formal legal enforceability required to be considered a contract, while a verbal promise to provide services does not necessarily imply that all the elements of a contract are met, such as a clear offer and acceptance or defined terms. Additionally, a contract signed only by the seller does not constitute a binding relationship since both parties need to agree and sign for it to be enforceable.