Rambo bought a car from the Ugly Used Car Agency under a written contract. She purchased the car in reliance on Ugly's agent's oral representations that it had never been in a wreck and could be driven at least two thousand miles without adding oil. Thereafter, Rambo discovered that the car had, in fact, been previously wrecked and rebuilt, that it used excessive quantities of oil, and that Ugly's agent was aware of these facts when the car was sold. Rambo brings an action to rescind the contract and recover the purchase price. Ugly objects to the introduction of oral testimony concerning representations of its agent, contending that the written contract alone governed the rights of the parties. What is the best argument that Rambo can make to defeat the objection?