Building C was purchased January 1, 2008, for $950,000. The straight-line method of depreciation was originally chosen. The building was expected to be useful for 25 years and have zeroresidual value. On January 1, 2011, a change was made from thestraight-line depreciation methodto the sum-of-the-years'- digits method. Estimate relating to the useful life and residual value remained the same. attachment