Final answer:
If the demand for money only depended on income for transaction purposes, monetary policy aimed at changing interest rates would be ineffective in influencing aggregate demand since money demand would not respond to interest rate changes.
Step-by-step explanation:
If the demand for money depended only on income, or the transaction motive, it would mean that individuals and businesses only hold money for spending and not for speculative or precautionary reasons. In this scenario, a key implication would be that monetary policy would become less effective in influencing aggregate demand through interest rate manipulation. Normally, monetary policy can adjust interest rates to encourage or discourage investment and consumption. However, if the transaction motive were the sole reason for holding money, changes in interest rates would have little to no impact on the quantity of money people want to hold.
Under the assumption of this scenario, the correct answer to the student's multiple-choice question would likely be Option A 'Monetary policy would be ineffective in boosting aggregate demand.' Because the demand for money does not respond to changes in interest rates, the standard transmission mechanisms of monetary policy would be disrupted, limiting its effectiveness. However, since this assumption deviates significantly from how money demand is commonly understood (with speculative and precautionary motives included), it's important to think critically about such scenarios.