Which statement best describes the parol evidence rule as it relates to supplementation of a written contract?

• A. A prior writing can never supplement
• B. A prior writing can supplement even if there is a merger clause
• C. A writing may supplement the agreement, unless there is a merger clause
• D. A writing may supplement the agreement, regardless of merger clause

Answer: (D)

Parol evidence rule limits what outside writings can do to a contract, but it doesn’t bar all supplementation. A prior writing can supply missing terms or reflect a collateral agreement that runs alongside the main contract, as long as those terms don’t contradict the written agreement. A merger clause states that the contract is the final expression, but it doesn’t automatically prevent supplementary terms from a prior writing if they’re consistent with the contract. Therefore, a prior writing may supplement the agreement regardless of a merger clause. For example, if a separate document sets a payment deadline not stated in the contract, that could supplement the contract without altering its core terms.