Core-periphery models are generally based on the idea that: A: all world religions are equally well developed

B: levels of social and economic development are fairly uniform between core areas and peripheral areas

C: sharp spatial contrasts in social and economic development exist between economic heartlands and outlying subordinate areas

D: the growth and prosperity of core countries has not been achieved at the expense of peripheral countries

E: the economic and social heart of a territory should be at its geographic center