On January 1, 2013, Zane Manufacturing Company purchased a machine for $40,000. The company expects to use the machine a total of 24,000 hours over the next 6 years. The estimated sales price of the machine at the end of 6 years is $4,000. The company used the machine 8,000 hours in 2013 and 12,000 in 2014. What is the book value of the machine at the end of 2014 if the company uses straight-line depreciation? A) $10,000 B) $28,000 C) $17,778 D) $20,000