Silken Inc Manufactures a Wide Range of Bath Products

Silken Inc manufactures a wide range of bath products.Its best-selling item is the 1 litre bottle of "Silky Soak" water softener.A large part of the reason for that success is the distinctive and easily recognized bottle in which "Silky Soak" has been sold for many years.Silken Inc recently applied to protect the rights that are connected with the appearance of the "Silky Soak" bottle.That application was,however,rejected.Which of the following is not a good reason to reject the application.

A) Silken Inc's application was based on the colour of the bottle.
B) Silken Inc had successfully applied for the same protection 10 years earlier.
C) The unique design of the bottle is purely functional in nature.
D) Silken Inc's application was based on the materials used in the bottle.
E) The bottle has a distinctive shape.