7. On January 1, 2018, a machine is purchased for $140,000. It is expected to have a useful life of 10 years, during which time it is expected to be used for 80,000 hours. The salvage value is $10,000. It is used for 5,000 hours in 2018 and 4,000 in 2019. What is the book value at 12/31/19? (The company uses the units-of-production method.) a) $117,000 b) $114,250 c) $124,250 d) $125,375