Final answer:
The Experience Rate System (Option B) measures an employer's unemployment claims to determine their unemployment tax rate. It does not concern individual employee experience or tax rates, or promotion eligibility.
Step-by-step explanation:
The Experience Rate System relates to unemployment and how it is measured within economic frameworks. Specifically, the answer to the student's question is B: The Experience Rate System measures the unemployment claims activity of an employer (ER) for purposes of determining the employer's unemployment tax rate. This system is designed to evaluate how frequently an employer's workers file for unemployment benefits and then uses that information to adjust the employer's contribution rate to the unemployment insurance system. It does not measure the experience or job placement of employees (EEs), their individual tax rate, or promotion eligibility. The unemployment rate itself is a critical economic indicator, with measurements such as the Current Population Survey (CPS) by the U.S. Census Bureau and the Bureau of Labor Statistics examining the labor force and its changes over time.