Frey, Inc. purchased a machine for $600,000 on January 2, 2017. The machine has an estimated useful life of 4 years and a salvage value of $100,000. The machine is being depreciated using the sum-of-the-years'-digits method. The December 31, 2018 asset balance, net of accumulated depreciation, should be: Select one: O a $250,000 O b. $350,000 Oc. $280,000 Od. $320,000 Oe. $450,000