I think the answer is oral modifier or oral statement but I am not sure

Tony's Pizza and Wisconsin Cheese Co-op negotiated for almost a month for a contract to sell a specialty blend of cheese to Tony's. When the final contract was written and signed, Tony's discovered that several terms that were discussed during the negotiations, which were favorable to Tony's but not to the Coop, were not included in the written agreement. What rule will stop Tony's from including those terms in the interpretation of the contract?

Oral statement Part performance Parol evidence Oral modifier