【单选题】

One factor that causes unemployment and earnings figures to over-predict the amount of economic hardship is
A．the recurrence of periods of unemployment for a group of low--wage workers.

B．the fact that unemployment counts do not include those who work for low wages.
C．the establishment of a system of record keeping that makes it possible to compile poverty statistics.
D．the prevalence, among low--wage workers and the unemployed, of members of families in which others are employed.