Benson Supply bought equipment at a cost of $24,000 on January 2, 2016. It originally had an estimated life of ten years and a salvage value of $4,000. Benson uses the straight-line depreciation method. In 2020, Benson decided the useful life likely would end on December 31, 2021, with a salvage value of $2,000. The depreciation expense recorded on December 31, 2020, should be

a. $2,000.

b. $7,000.

c. $4,000.

d. $3,500.