13. On January 1, Year 1, Sophia Company purchased an asset that cost $100,000. The asset had an expected useful life of five years and an estimated salvage value of $20,000. Sophia uses the straight-line method for the recognition of depreciation expense. At the beginning of the fourth year, the company revised its estimated salvage value to $10,000. What is the amount of depreciation expense to be recognized during Year 4? a. $19,000 b. $16,000 C. $8,400 d. $21,000