What represents the total amount of depreciation expensed since the asset's date of purchase?

Accumulated depreciation is the correct answer because it specifically refers to the total amount of depreciation that has been recognized and expensed for an asset since it was acquired. This figure is recorded in the financial statements as a contra asset account, which reduces the carrying value of the asset on the balance sheet.

As an asset ages and is used over time, it depreciates, reflecting its wear and tear or obsolescence. The accumulated depreciation figure helps users of the financial statements understand how much of the asset’s original cost has been allocated as an expense to date, and it gives insight into the asset's remaining useful life.

The other options represent different concepts. Net book value refers to the carrying amount of an asset after subtracting accumulated depreciation from its original cost. A depreciation schedule is a document that outlines how an asset's depreciation will be applied over its useful life, detailing the annual depreciation expense. Carrying amount, similar to net book value, is the asset's value on the balance sheet but doesn’t represent the total depreciation expensed. Instead, it is the original cost minus accumulated depreciation.