A company used straight-line depreciation for an item of equipment that cost $12,000 had a salvage value of $2,000, and had a five-year useful life. After depreciating the asset for three complete years, the salvage value was reduced to $1,200 and its total useful life was increased from five years to six years. Determine the amount of depreciation to be charged against the machine during each of the remaining years of its useful life:

a.       $1,000

b.       $1,800