Explanation:

- The equilibrium level of income is determined where total injections (such as investments and government spending) equal total withdrawals (like savings and taxes) in the economy.

- Option 1: A shift

- This occurs when changes in injections and withdrawals lead to a new equilibrium income level. When there’s an increase in injections or a decrease in withdrawals, the equilibrium income level shifts upwards. Conversely, if injections decrease or withdrawals increase, the equilibrium shifts downwards.

- This is the correct answer.

- Option 2: No shift

- This would imply that injections and withdrawals are perfectly balanced, maintaining the existing equilibrium without change.

- Option 3: A dispersal

- This term is generally not used in the context of equilibrium income and might imply a spreading out rather than a shift.

- Option 4: No change

- Similar to option 2 but more about the static nature of the equilibrium.