The correct answer is - D. the Euphrates River.
The Euphrates River is a river that is not part of the African continent. It is flowing through the so called Fertile Crescent, in the Middle East region, in Western Asia, and most of its flow is through the country of Iraq.
This is a river very well known, alongside the Tigris River, that it is the place where the human civilization had started, where agriculture developed, and where the great Sumerian civilization thrived, followed by the Babylonian and Assyrian in the centuries after them.