The right answer is Sodium chloride.
Sodium chloride is a chemical compound whose formula is NaCl. Everyone knows the taste because it is, more simply, table salt.
Let's take a pool 50 meters long and 15 meters wide and fill it with sea water. Then let's go to his analysis. We find:
1400 tons of pure water
50 tons of sodium chloride
2 tons of magnesium
1 ton of sulfur
And then much less frequent elements