Which of the following was a continuity in the development of african states in the period circa 1200–1450 ?

a. african states such as ethiopia maintained close contacts with south and east asian states across the indian ocean but rarely had contacts with europe.

b. despite geographical barriers, some african states were able to maintain diplomatic and cultural contacts with the broader afro-eurasian world.

c. most african states rejected traditional forms of international diplomacy, such as dynastic marriages and tribute payments.

d. african states needed to maintain friendly diplomatic relations with europe in order to expand their empires.