i believe the answer is c.
What do you need help with?
Answer:
They built walls around their cities for protection
Explanation:
Sargon the Great
Around 2,300 BC, the independent city-states of Sumer were conquered by a man called Sargon the Great of Akkad, who had once ruled the city-state of Kish. Sargon was an Akkadian, a Semitic group of desert nomads who eventually settled in Mesopotamia just north of Sumer.
I think the letter B is the answer