The correct answer is A. Distillation.
Distillation is a process of separating a mixture of liquids based on their boiling points. The mixture is heated until the liquid with the lowest boiling point vaporizes. The vapor is then condensed back into a liquid and collected. This process can be repeated to separate multiple liquids from a mixture.
Evaporation is a process of converting a liquid into a gas or vapor. It is a physical change that does not involve a chemical reaction. Evaporation occurs when the molecules of a liquid have enough energy to escape from the surface of the liquid and enter the air. The rate of evaporation depends on the temperature of the liquid, the surface area of the liquid, and the humidity of the air.
Filtration is a process of separating solids from liquids or gases. It is a physical process that does not involve a chemical reaction. Filtration occurs when a liquid or gas is passed through a filter. The filter traps the solids, and the liquid or gas passes through the filter.
Fractional distillation is a process of separating a mixture of liquids that have different boiling points. It is a more complex process than distillation. Fractional distillation is used to separate mixtures of liquids that have close boiling points.
In the case of sea water, distillation is the most effective process for purifying it. Distillation removes all of the dissolved salts and other impurities from the water, leaving behind pure water.