Equipment with a cost of $160,000 has an estimated residual value of $10,000 and an estimated life of 4 years or 12,000 hours. It is to be depreciated by the units-of-production method. What is the amount of depreciation expense for the first full year, during which the equipment was used 3,300 hours?

a.$44,000.

b.$40,000.

c.$37,500.

d.$41,250.

e.$42,500.