Essentially, a coupe is a passenger car with a sloping or truncated rear roofline and two doors. By definition, a coupe has a fixed-roof and may feature one or two rows of seating. There is an ongoing debate as to whether a coupe must have two doors or whether four-door cars can possibly be considered coupes. Certain sporty-looking models like the Mercedes-Benz CLS C-Class have been marketed as four-door coupes or quad coupes.