As the net book value of fixed assets expires, it is recognized as which type of expense?

The recognition of the net book value of fixed assets expiring takes the form of depreciation expense. This expense reflects the systematic allocation of the cost of tangible fixed assets over their useful lives, representing the consumption of the asset's economic benefits. Depreciation expense is recorded to match the cost of the asset with the revenue it generates, thereby adhering to the matching principle in accounting.

For each reporting period, the depreciation expense reduces the carrying amount of the fixed assets on the balance sheet and the net income on the income statement, providing a more accurate picture of the company's financial performance and position. By allocating the expense over multiple periods, it ensures that the financial statements reflect the declining value of the asset as it is utilized in the business operations.

The other options do not fit this scenario because asset impairment expense pertains to a permanent reduction in the carrying amount of an asset when its market value falls below its book value, cost of goods sold relates to the direct costs attributable to the production of goods sold by a company, and operating expenses are ongoing costs for running a business that do not include depreciation specifically associated with fixed assets. Thus, the classification of the expense as depreciation reflects its nature and treatment correctly.