Machiel Manufacturing Acquired a $60,000 Machine on January 1,2009

Machiel Manufacturing acquired a $60,000 machine on January 1,2009.The machine is estimated to have a useful life of 4 years,and a residual value of $10,000.For units-of-production depreciation purposes,the machine is expected to produce 500,000 units.Machiel Manufacturing uses units-of-production depreciation,and the company produces 80,000 units in 2009; 130,000 units in 2010; 160,000 units in 2011 and 70,000 units in 2012; what is the net book value of the machine at December 31,2012?

A) $ 8,000
B) $13,000
C) $12,800
D) $16,000
E) $37,000