Answer:
My car looks brand new with its rusted fender and dented doors.
Explanation:
Sarcasm is when someone say something opposite to the actual scenario, to mock something just to make it funny in a delighted way of humor. "My car is brand new" is totally opposite to "it's rusted fender and dented doors".
Clearly his car is old, has rusted fender and dented doors which means poorly managed, but he for the sake of laugh or to make it funny mentioned it a brand new car.