Stan buys a 1966 Mustang with the intention of repairing, restoring and selling it. He anticipates that it will cost him $10,000 to purchase, repair and restore the car, and that he can sell the finished car for $13,000. When he has spent a total of $10,000 on the project, he discovers that he needs to replace the engine. It will cost Stan $4,000 to replace the engine. He can sell the car without the new engine for $9,000.What should he do?