Which statement best characterizes power relations among the centers of Eurasian civilizations as they approached the year 1450? a. Islamic caliphates are reaching the height of their power and influence
b. Ming rulers of China have redoubled their efforts to move to the center of maritime trading networks in the East Asian and Indian Ocean
c. A power vacuum of sorts has opened, as Byzantine, Abbasid, and Ming Chinese powers become less of a force in global affairs
d. Western Europe dominates world trade
e. South and East Asia are no longer important sources of luxury items in long-distance trade networks and become increasingly isolated