Which of these liquids has the lowest freezing point?
ocean water
lake water
bottled water
river water

Ocean water freezing point: -4°C
Fresh water freezing point (Lake, bottled, river): 0°C

So the answer is ocean water.

Answer is ocean water. In a chemical point of view, the amount of salt/solute in water is directly proportional to the lowering of freezing point (called freezing point depression)... same goes with it's boiling point which goes higher (bp elevation) as the amount of dissolved salts/solute increases.

In some developing nations the percentage of the animal protein from fish in the diet can be as high as 25 percent.  about 85% of fish caught is used for human consumption.  the remainder is converted into fishmeal and fish oil.