问题如下：
Which of the following best explains the phenomenon that unemployment rate is a lagging economic indicator of the business cycle?
选项：
A. Underemployed people tend to quit their job very often.
B. It is typical of businesses to lay off people reluctantly.
C. Entrepreneurs have an urgent need of new workers.
解释：
B is correct.
Unemployment rate is a lagging economic indicator of the business cycle because are reluctant to lay off people.
考点：Unemployment
解析：因为在经济刚开始不景气的时候，企业主会通过减少工人工作小时数的方法调节生产，只有当经济进一步衰退时才会考虑裁员，所以B选项说法正确。
经济不景气的时候企业主无意培训新员工，工人也无意频繁辞职，所以A,C选项都错误。
请问如何看出本题题干说的是萧条期的情形？
