On January 1, year 2, an intangible asset with a 35-year estimated useful life was acquired. On January 1, year 6, a review was made of the estimated useful life, and it was determined that the intangible asset had an estimated useful life of 45 more years. As a result of the review
　　A. The unamortized cost at January 1, year 6, should be amortized over a 40-year life.
　　B. The original cost at January 1, year 2, should be amortized over a 50-year life.
　　C. The unamortized cost at January 1, year 6, should be amortized over a 45-year life.
　　D. The original cost at January 1, year 2, should be amortized over the remaining 30-year life.
　　Answer:C
　　C is corrent because if the estimated useful life of an intangible asset is revised, the unamortized cost should be allocated over the remaining periods of the new useful life.
　　A is incorrect because the period of amortization would not reflect the estimated useful life.
　　B is incorrect because adjustments are applied prospectively.
　　D is incorrect because it does not reflect the revised useful life.