On January 1, 2010, Bart Company purchased equipment at a cost of $135,000. The equipment was estimated to have a useful life of 5 years and a salvage value of $15,000. Bart uses the sum-of-the-years'-digits method of depreciation. What should the accumulated depreciation be on December 31, 2012? Select one: O a $108,000 O b. $84,000 Oc. $72,000 O d. $54,000 O e. $96,000