Correct option is A
In the circular flow of income model, an injection is any addition to the economy’s circular flow that increases income and output. Exports to foreigners represent an injection,
• Injections include investment, government spending, and exports.
• Injections increase aggregate demand and boost national income.
• The equilibrium in the circular flow is achieved when total injections = total leakages.
• Exports result in foreign income inflow, stimulating domestic production and employment.