Final answer:
A macroeconomist would study the effect of changes in the money supply on the inflation rate, as it involves the examination of economy-wide phenomena and broad fiscal policies affecting aggregate spending and overall economic performance.
Step-by-step explanation:
Among the options provided, the scenario that would likely be studied by a macroeconomist rather than a microeconomist is D. the effect of changes in the money supply on the inflation rate. Macroeconomics deals with the economy as a whole and the decisions that shape the entire nation's economy. Macroeconomists analyze broad factors such as changes in the money supply, inflation, and aggregate spending, along with how fiscal policies like taxes can impact the real GDP and unemployment rate.
By contrast, microeconomics focuses on individual behaviors and the effects of decisions on specific sectors or markets. For instance, the impact of a hurricane on prices in the orange industry or the effects on fuel consumption due to an increased gas tax would fall under microeconomic study because they concern narrower subjects rather than the economy-wide implications.