Which of the following is NOT a requirement for an enforceable contract?

In contract law, while a written document can provide clarity and evidence of the terms agreed upon, it is not always required for a contract to be enforceable. Many contracts can be valid and legally binding even if they are oral, depending on the nature of the agreement and applicable laws.

The requirements for an enforceable contract generally include the following key elements:

1. Legality of subject matter ensures that the contract is for a lawful purpose.

2. Consideration involves something of value exchanged between the parties.

3. Acceptance of the offer signifies that one party has agreed to the terms set forth by the other.

Since a written document is not universally mandated for every type of contract, the correct answer identifies that requirement as not essential for enforceability, distinguishing it from the other critical elements that are always necessary.