A company purchased a vehicle with an estimated useful life of 8 years. The vehicle cost $20,000 and its estimated salvage value is $2,000. After 4 years of straight-line depreciation, the asset's total estimated useful life was revised from 8 years to 6 years and there was no change in the estimated salvage value. The depreciation expense in year 5 equals:
$2,250.
$2,500.
$4,500.
$4,750.
$5,000.