Byzantium and China in the Third-Wave Era Were Similar Because

Byzantium and China in the third-wave era were similar because both

A) collapsed at the end of the classical era,never to recover.
B) influenced third-wave civilizations that developed in their regions.
C) were threatened by the Islamic Arab empire in the 600s and 700s.
D) were ruled by emperors who were figureheads with no power.