Martin Corporation purchased a depreciable asset for $630,000 on January 1 Year 1. The estimated salvage value is $63,000, and the estimated total useful life is 9 years. The straight-line method is used for depreciation. In Year 4 Falcon changed its estimates to a useful life of 5 years with a salvage value of $105,000. What is Year 4 depreciation expense? Select one O a $63,000 O b. $105,000 Oc $168,000 Od $189,000 Oe None of these choices