Which of the following is not appropriate in calculating national income figures?

The depreciation method is not appropriate in calculating national income figures. Depreciation is a measure of the wear and tear on capital goods, such as machinery and equipment, over time. It represents the decline in the value of these assets as they are used in the production process. While depreciation is an important concept in accounting and financial analysis, it is not included in national income figures because it is not a measure of current production or income. Instead, national income figures are calculated using methods that focus on current output, income, and expenditure, such as the output method, income method, expenditure method, and value added method.