Final answer:
When an economy is producing at potential GDP according to the neoclassical model, cyclical unemployment will be zero, but the overall unemployment rate will never be at 0% due to frictional and structural unemployment.
Step-by-step explanation:
Using a neoclassical model, when an economy is producing at potential GDP, the level of cyclical unemployment will be zero (A). This is because cyclical unemployment is the result of fluctuations in the business cycle and occurs when the economy is producing below its potential GDP. At potential GDP, the economy is considered to be at full employment, although this doesn't mean the unemployment rate will be at 0% due to the presence of frictional and structural unemployment. It's important to note that labor market dynamics, such as the entry and exit of people into the labor force, cause the unemployment rate to never fall to absolute zero.
Within the neoclassical zone, shifts in aggregate demand (AD) have negligible effects on output levels and employment because the economy is already at or near full capacity. The key way to increase real GDP in this zone is through a shift in aggregate supply (AS) to the right. Shifts in AD mainly create price level changes rather than affect employment levels. The natural rate of unemployment, which consists of frictional and structural unemployment, is what remains even when the economy is at potential GDP.