The correct answer is B) the death of Alexander the Great.
The event that is considered to be the start of the "Hellenistic Era" is the death of Alexander the Great.
During the Hellenistic era, the Greek Hellenist culture expanded all over the territories conquered by Alexander the Great, including the Asian territories such as Syria or North Africa Territories such as Egypt. It started in 323 BC after the death of Alexander the Conqueror and historians consider it ended in 31 BC when Rome conquered the Lagyd, Egypt.