On January 1 of year 1, the Li Company purchased an asset that cost $80,000. The asset had an expected useful life of five years and an estimated salvage value of $16,000. Li uses the straight-line method for the recognition of depreciation expense. At the start of the fourth year of use, the company revised its estimated salvage value to $8,000. Based on this information, calculate  the amount of depreciation expense to be recognized at the end of Year 4.

a. $12,800.

b. $16,800.

c. $33,600.

d. $20,800.