Which of the following is NOT an element of a valid contract?

A valid contract is formed based on several essential elements, and one of them is not strictly about existing in written form. Offer and acceptance establish that one party proposes terms and the other agrees to them. Consideration refers to something of value that is exchanged between the parties, which incentivizes both sides to fulfill their contractual obligations. Legal purpose ensures that the contract's purpose is lawful and not contrary to public policy.

While having written documentation is often beneficial and in many cases required for enforceability—especially in contracts that involve significant amounts or are governed by specific regulations—it is not an absolute requirement for a contract to be valid. Verbal contracts can be legally binding if they meet the necessary elements of offer, acceptance, consideration, and legal purpose. Thus, while written evidence can support clarity and proof of the terms, its absence does not invalidate the contract under most circumstances, making it the correct choice for something that is not a fundamental element of a valid contract.