In macroeconomics, national expenditure is typically measured as the sum of all spending in an economy on final goods and services. This is the expenditure approach to calculating Gross Domestic Product (GDP). The components of GDP under the expenditure approach are: 1. Consumption expenditure (C): Spending by households. 2. Investment expenditure (I): Spending by firms on capital goods, inventory, and residential structures. 3. Government expenditure (G): Spending by the government on goods and services. 4. Net Exports (X- M): Exports minus imports. The options provided only list C, I, and G. Therefore, "All of the above" referring to these three components is the most appropriate answer in this context.