Castle Rock Owns a Machine That It Purchased on Jan

Castle Rock owns a machine that it purchased on Jan 1,2016 for $400,000.The machine had an estimated useful life of 10 years with a production capacity for 80,000 units and was expected to have no residual value.The company uses the units-of-production method to record depreciation.The machine produced 15,000 units in 2016,18,000 units in 2017 and 25,000 units in 2018.The machine was sold on December 31,2018 for $350,000.What was the depreciation expense for 2018?

A) $39,000
B) $40,000
C) $90,000
D) $125,000