The correct answer is A. Dead Sea.
The Dead Sea is a salt lake bordered by Jordan to the east and Israel and the West Bank to the west. It is the lowest lake on Earth, sitting 430.5 meters (1,412 ft) below sea level. The Dead Sea is also the saltiest lake in the world, with a salinity of 342 grams per liter. This is about 10 times saltier than the ocean, and so dense that swimmers float effortlessly on its surface.
The high salinity of the Dead Sea is due to its location in a desert climate. The lake receives very little rainfall, and the only water that flows into it is from the Jordan River. This water evaporates quickly, leaving behind the salt and other minerals.
The Dead Sea is a popular tourist destination, known for its therapeutic mud and its ability to relieve skin conditions. It is also a major source of salt and potash.
The other options are incorrect because they are not as salty as the Dead Sea. The Red Sea has an average salinity of 41 grams per liter, the Black Sea has an average salinity of 18 grams per liter, and the Mediterranean Sea has an average salinity of 38 grams per liter.