Choice "B" is correct. Intangibles such as goodwill, licenses, franchises, trademarks and covenants not to compete may be amortized using the straight line basis over a period of 15 years, starting with the month of acquisition. Note, the difference for GAAP purposes: Intangible assets with indefinite lives are subject only to an impairment test, and intangible assets with finite lives are amortized over those lives and also subject to an impairment test.
Choice "c" is incorrect. The time certain does not impact the amortization period.
Choice "d" is incorrect. The option to extend does not impact the amortization period.
Choice "a" is incorrect. 17 years is longer than required to amortize intangible assets.