Answer:
The correct answer is D) The cataracts became passable
Step-by-step explanation:
The River Nile has supported various civilizations since thousands of years including the famous Ancient Egyptian Civilization.
While the area is generally known for its dry desert, the Nile River used to flood every year. This overflow left a lot of black silt which made the surroundings areas very fertile.
The fertile land meant people starting living and farming near the river, giving life to thousands of years of continuous human presence.
However, the problem was cataracts are not caused by Nile floods.