Answer: A. Alexandria, Egypt became a centre for learning
E. Greece was unified under one ruler
Explanation: Alexander the Great was a great conqueror, he arrived in his conquests all the way from India, Persia, Egypt. He founded a city in Egypt, named after him Alexandria, which became the centre of learning, the capital of ancient knowledge, also known for its famous Alexandrian library, which supports the claim of Alexandria as the centre of knowledge and learning.
Before Alexander the Great stood on the throne, Greece was, in the recent or long past, largely divided into city-states both because of geographical conditions and because of political relations between the rulers of these cities. After Alexander Greece, the united empire became one of the largest in the ancient world.
It was also the time when Greece in terms of religion and philosophy accepted the most influences from the conquered countries, so that the then Greek religion and philosophy had the most foreign influences ever, from Indian and Persian to Egyptian influences.
Trade with the aforementioned regions and countries also flourished with new ideas, so that Greece was not isolated in any respect, trade, ideological, cultural, religious, on the contrary.