Where Was the Cradle of Chinese Civilization

Where was the cradle of Chinese civilization?

A) Centered on the great Northern Plain's grasslands, where millet grew abundantly.
B) South of the Yangtze River's swamplands, where there were many rice farms.
C) The Yellow River valley, where rich soils made a wide variety of crops possible.
D) Along the Yangtze River, but over time became centered around the Yellow River valley.
E) It actually began with non-Chinese peoples who were still hunter-gatherers.