The correct answer is A) The mountainous terrain of Egypt was uninhabitable, so civilizations could only prosper near the Nile where the land was flat.
Note the locations of settlements across upper and lower Egypt. The option that most likely influenced civilizations to settle in these locations is "The mountainous terrain of Egypt was uninhabitable, so civilizations could only prosper near the Nile where the land was flat."
Early humans decided to settle in close to river banks for the many advantages water represented. During the Neolithic Revolution, early humans learned agriculture techniques that allowed them to finally stop being nomads and settle in to farm the fields. Ancient Egyptians settled in next to the Nile River. The flooding of the river produced fertile soil and they could grow crops. Something similar happened in places such as Sumeria, where they settled in between the Tigris and Euphrates Rivers.