In the Onion Metaphor the Middle Layer of People Consist

In the onion metaphor the middle layer of people consist of:

A) People that receive assistance for two to eight years,and are on-and-off again users of the public welfare system.
B) People that enter the system due to a discrete event,and use the system for two or fewer years.
C) People that have serious physical and emotional impairment
D) People who are systems dependent and receive assistance for eight or more years.