Final answer:
The net book value of a depreciable asset is the difference between the asset's original cost and its accumulated depreciation, representing the asset's currently recorded value on a balance sheet.
Step-by-step explanation:
The net book value of a depreciable asset is not the difference between the asset's cost and depreciation expense, nor is it the amount for which the asset should be insured or the fair value of the asset. Instead, the correct answer is D. the difference between the asset's cost and accumulated depreciation. Accumulated depreciation represents the total amount of depreciation expense that has been recorded against the asset over its life. Therefore, the net book value is essentially the original cost of the asset minus all the depreciation expenses that have been applied to it until the present date. On a balance sheet, this figure represents the currently recorded value of the asset.