I did a little research and it looks like the answer is A.
Answer:
Battle of Salamis
Explanation:
Battle of Salamis, (480 bc), battle in the Greco-Persian Wars in which a Greek fleet defeated much larger Persian naval forces in the straits at Salamis, between the island of Salamis and the Athenian port-city of Piraeus.
Answer: A. India
Explanation: After India, the next-largest Commonwealth countries by population are Pakistan
It was also an exchange of culture. When people from different cultures met they learned about each other and shared ideas.