A Car Repair Shop Attempts to Differentiate Itself from the Other

A car repair shop attempts to differentiate itself from the other repair shops in town by washing the customer's car for free before it is returned. What is the principle weakness with using this as a method of differentiating the business from the competition?

A) It is not a desired service.
B) The service does not create time utility.
C) The service can be easily imitated.
D) The free car wash does nothing to improve the problem with fluctuating demand for services.
E) The problem with service heterogeneity is almost totally eliminated with the free car wash.