Final answer:
The Keynesian view attributes business cycle fluctuations to changes in aggregate demand and supports government intervention, while the neoclassical/monetarist view focuses on aggregate supply and market self-correction. Therefore, the correct option is A.
Step-by-step explanation:
The two mainstream views of the cause of business cycles differ primarily in their emphasis on either demand-side or supply-side factors. The Keynesian view argues that business cycle fluctuations are due to changes in aggregate demand. Keynesians believe that the economy may not automatically return to full employment and thus support active government intervention to mitigate recessionary and inflationary periods. They emphasize the role that fiscal policy, like government spending and taxes, can play in stabilizing the economy.
In contrast, the neoclassical view, which can align closely with Monetarist beliefs, focuses on aggregate supply factors. This perspective suggests that the underlying mechanisms of the markets for output and employment are the primary determinants of economic cycles. Neoclassicists advocate for the economy's ability for self-correction and often emphasize long-term economic growth and labor market functioning, suggesting less need for government intervention.
Therefore, the correct answer to the student's question is: a) the Keynesian view emphasizes demand-side factors, while the Monetarist view emphasizes supply-side factors.