A depreciable asset has an estimated 15% salvage value. At the end of its estimated useful life, the accumulated depreciation will equal the original cost of the asset under which of the following depreciation methods? Select one: O a Straight-line and Units-of-Output O b. Straight-line, but not Units-of-Output Oc Units-of-Output, but not Straight-line Od Neither Straight-line nor Units of Output