Comparing with unemployment rate with employment rate, which of the following is NOT correct? a. Unemployment rate takes the group of "out of labor force" into account. b. Compared with unemployment rate, employment rate is better because it concerns the hidden unemployment in the out of labor force group. c. Compared with employment rate, unemployment rate in a labor market usually has a larger variation. d. It has limitation because some policy shocks unrelated to unemployment or labor market situation such changes in fertility and school enrollment rates, will affect the number of the employment rate as well.