Archaeological Sites at Erlitou and Sanxingdui Reveal That

Archaeological sites at Erlitou and Sanxingdui reveal that

A) . the Yellow and Yangzi valleys remained largely undeveloped until the first millennium B.C.E.
B) foraging persisted as the primary form of food collection in the Yellow and Yangzi valleys well into the second millennium B.C.E.
C) several complex and highly developed civilizations existed in China before the Shang dynasty.
D) Chinese civilization remained largely isolated from international trade networks during the Bronze Age