The correct answer to this open question is the following.
Unfortunately, you did not attach the map, neither the options for this question.
However, doing some research, we can answer the following.
The water source that was the most influential to the development of ancient Egyptian civilization was the Nile River.
It was the most important water source and influenced the development of Ancient Egypt in that the flooding of the Nile left rich soil to grew different crops and the Nile also served as a transportation canal that improved trade in that time.
According to historians, that is why Ancient Egyptians decided to settle next to the Nile River, due to the many benefits this represented.