An agreement that is enforceable in law is a contract. A contract is an agreement between two or more parties that creates legal obligations between them. In other words, it is a legally binding agreement that can be enforced through the courts. To be a valid contract, there must be an offer, an acceptance, a consideration, and an intention to create legal relations. Once all of these elements are present, the parties are bound to fulfill their respective obligations as outlined in the contract. Therefore, a contract is the only option among the given choices that fits the definition of an enforceable agreement in law.