Types of Injections into the circular flow.

• A. Investment (I)
• B. Government Expenditure (G)
• C. Exports (X)
• D. Investment (I), Government Expenditure (G) and Exports (X)

Answer: (D)

Injections into the circular flow are spending additions that push overall demand up and increase national income. The three main sources are investment in capital projects, government expenditure on goods and services, and spending on exports by foreigners. Each of these puts money back into the economy: investment funds new production and creates incomes for workers and suppliers, government spending directly adds to demand for goods and services, and exports bring income from abroad for domestically produced goods.

The question asks for the types of injections, and together those three categories cover the full set. While each of investment, government expenditure, and exports can act as an injection on its own, the complete list that represents all injections is investment, government expenditure and exports.