Which of the following is NOT required for a valid real estate contract?

A valid real estate contract requires: (1) offer and acceptance (mutual assent or 'meeting of the minds'); (2) consideration (something of value exchanged, even if symbolic); (3) legal purpose (the contract cannot require an illegal act); (4) competent parties (legally capable of contracting); and (5) in most cases, the writing requirement of the Statute of Frauds (real estate contracts must generally be in writing to be enforceable). A notarized or witnessed signature is not generally required for the contract itself, though some states require it for the deed transferring title. Verbal real estate contracts can be valid in principle but are nearly impossible to enforce because the Statute of Frauds requires writing.