No problem! It's important to differentiate between the Classical and Keynesian theories in macroeconomics. Classical economists believe in the self-regulating nature of the economy, where markets adjust themselves to reach equilibrium. They often advocate for limited government intervention and believe that supply creates its own demand.
In contrast, Keynesian economists argue that in certain situations, the economy may not self-correct and that government intervention is necessary to stabilize the economy. They focus on the role of aggregate demand in shaping economic outcomes.
If you are specifically studying the Classical Macroeconomic Theory, then the answer to the question would indeed involve supply-side measures to address an inflationary gap. These measures could include policies that promote increased production and efficiency in the economy, such as reducing regulations and taxes that hinder business activity. By improving productivity and expanding aggregate supply, the economy can reach a long-run equilibrium without relying on demand-side policies.
However, if your instructor intended to refer to Keynesian economics when mentioning the "classical" economist, then contractionary fiscal policy, as I mentioned earlier, would be the appropriate response to reducing an inflationary gap. This would involve reducing government spending or increasing taxes to reduce aggregate demand and bring it back in line with aggregate supply.
It's always important to clarify the specific economic theory being referred to in order to provide the most accurate answer.