Correct option is C
The correct answer is: (c), A and D only
The core region is the focus of economic growth with an urban nucleus.
Downward-transitional areas represent areas of settlement that are stagnant or declining because of decline in the resource base or industrial structure.
Information booster:
Friedmann’s core periphery model (1966) is a model on economic development based on observation that development is rarely evenly distributed, be it regional, national or international scale. There is tendency for growth to become concentrated at favoured locations (core) which, in turn, leave their wake areas to stagnation or decline (periphery).
Developed countries are known as the core, and the Less developed countries are referred to as the periphery.