To determine which body of water is closest to the Mediterranean Sea among the options provided, we need to consider their geographical locations:
- Lake Victoria is located in East Africa, far from the Mediterranean.
- Niger River flows through West Africa but is still quite distant from the Mediterranean Sea.
- Nile River originates in East Africa and flows northwards through Sudan and Egypt before emptying into the Mediterranean Sea. It is the closest in proximity to the Mediterranean Sea.
- Lake Chad is located in Central Africa, also far from the Mediterranean.
From this analysis, the Nile River is the body of water that is closest to the Mediterranean Sea.