How did the people of nubia and egypt benefit from the geography of the nile

There were many benefits to the geography of the Nile. Along the river are fruit trees and the river contains lots of fish. For six months, the Nile would flood and leave black silt on the soil which would eventually grown into wheat beans and barley. They were also able to dig canals to make fresh water.
The people also used the reeds in the nile as papyrus paper and even made the first calendars writing on them and papyrus was used for many other things as well such as boats and sandals.
The Nile was also surrounded by many large swathes of desert and enemy attacks were very rare, as it was extremely difficult to reach the ancient civilizations along the Nile.

It’s either d or b ! but it might be b