The correct answer is C) this is where many of the low-class residents would work, and they need to be able to walk to work.
Geographer Burgess proposed a land-use model, where the low-class residential area is located just beyond the factory/industrial ring because this is where many of the low-class residents would work, and they need to be able to walk to work.
The Burgess' land-use model is also known as the concentric zone model, which refers to the idea that the land and work have more value in the central zone of the city, also called the business district. This is the place were people, and business has their daily activities. Around downtown, there is the factory zone, followed by a zone of transition, then a working-class zone, followed by a residential zone, and finally, a commuter zone.