Answer:
The correct answer is A. The river described in the statements is the Nile river.
Step-by-step explanation:
The Nile is the longest river on earth. The river is estimated to be between 6300 and 7200 km long. The river Kagera, which flows into Lake Victoria in Uganda, is thought to be the source of the Nile. From there, the mighty river flows through Uganda, Sudan and Egypt before it flows out into the Mediterranean. On the journey north, the river receives inflow from a series of subsidiaries. The most important of these is the so-called "Blue Nile", which originated in Ethiopia.
In ancient Egypt, the Nile basin was thoroughly documented, precisely because it formed the basis for all economic growth and decline in the area.