Final answer:
The equilibrium unemployment rate is the long-run unemployment rate that the economy tends to return to over time, also known as the natural rate of unemployment. It is shaped by structural market forces and government institutions and includes frictional and structural unemployment.
Step-by-step explanation:
The equilibrium unemployment rate is d) the long-run unemployment rate to which the economy tends to return over time. This refers to the natural rate of unemployment that includes joblessness caused by the market and institutional forces in the labor market, such as frictional unemployment and structural unemployment.
The natural rate of unemployment is not determined by short-term economic fluctuations, but by how well the structures of the market and government institutions match workers with available jobs over the long term. It reflects the number of people jobless due to the constant dynamics of the labor force, including those changing jobs or those who have skills that do not match current market demands. Public policies that may either encourage or discourage job creation also play a role in shaping the natural rate.