In the circular flow of income model of an economy, which one of the following relationships is correct?
National Output ≡\equiv≡ National Income ≡\equiv≡ National Expenditure
National Output + Injections ≡\equiv≡ National Expenditure + Withdrawals
National Income −-− Withdrawals ≡\equiv≡ National Expenditure + Injections
National Output ≡\equiv≡ Injections ≡\equiv≡ Withdrawals