The coices that apply are A and E.
Greece was unified under one ruler. Alexander's father, King Philip of Macedon, invaded and conquered the Greek city-states, taking advantage of the fact that the Greek city-states were divided by years of squabbling and infighting. After his father was able to unite Greece, Alexander's more important legacy was spreading the Greek culture, also known as Hellenism, across his empire. In fact, this era was known as the Hellenistic Age because of the powerful influence that Greek culture had on other people.
Similarly, Alexandria, Egypt became a center for learning. After he took the throne in 336 B.C.E., and vowing to complete the plans of his father. He conquered Egypt and founded a city at the mouth of the Nile River which he named Alexandria after himself. This city, became a cosmopolitan, diverse, bustling center of trade, the arts, and ideas.