Which of the following best defines a contract?

A contract is best defined as a binding agreement enforceable by law. This definition captures the essential elements of a contract, which include an offer, acceptance, consideration (something of value exchanged), and the intention to create legal obligations between the parties involved.

In a legal context, for an agreement to be considered a contract, it must meet certain criteria that ensure the agreement has the capacity to be enforced by a court of law. This means that if one party fails to fulfill their part of the agreement, the other party has the right to seek legal recourse.

Other options such as a verbal agreement between friends, a recommendation for service, or a casual arrangement do not fulfill the legal requirements necessary to be classified as a contract. A verbal agreement might not necessarily be enforceable unless it meets the specific criteria, a recommendation does not imply a binding obligation, and a casual arrangement typically lacks the formalities required for legal enforceability. Thus, option B is the most accurate representation of a contract's definition.