A depreciable asset with a three-year life has a first cost of $30,000 with a $6,000 salvage value. The machine's operating cost is $10,000 in year one, $12,000 in year two and $14,000 in year three. According to the straight line method, the depreciation charge in year 2 is closest to:?
a. $20,000
b. $22,000
c. $8,000
d. $10,000