Final answer:
The book value of a depreciable asset cannot be less than its residual value, as this is the estimated worth of the asset at the end of its useful life after considering depreciation.
Step-by-step explanation:
The book value of a depreciable asset is calculated as its historical or capitalized cost minus its accumulated depreciation. This reflects the asset's net value on a company's balance sheet. Among the options provided, the book value of a depreciable asset can never be less than its residual value (also known as salvage value), which is the estimated amount that an asset is expected to be worth at the end of its useful life after depreciation has been fully accounted for. Historical cost, market value, and capitalized cost are not the correct answers since book value does indeed decrease below these amounts over time with depreciation. The accumulated depreciation is part of the calculation and does not serve as a minimum threshold for book value.