Can someone please tell me why it's C?

Broadway Corporation was granted a patent on a product on January 1, 1998. To protect its patent, the corporation purchased on January 1, 2009 a patent on a competing product which was originally issued on January 10, 2005. Because of its unique plant, Broadway Corporation does not feel the competing patent can be used in producing a product. The cost of the competing patent should be

a.amortized over a maximum period of 20 years.

b.amortized over a maximum period of 16 years.

c.amortized over a maximum period of 9 years.

d.expensed in 2009.