A machine with a cost of $100 000 has an estimated residual value of $10 000 and an estimated life of five years or 30 000 hours.

It is to be depreciated by the units-of-activity method.

What is the amount of depreciation for the second full year, during which the machine was used 6 000 hours?

a) $9,000

b) $16,000

c) $20,000

d) $18,000