The correct answer is (d). Reverse osmosis is a water purification process that uses pressure to force water molecules through a semipermeable membrane, which removes dissolved salts and other impurities.
(a) Deliquescence is the process by which a substance absorbs water from the air until it dissolves.
(b) Efflorescence is the process by which a substance loses water from its surface, often as a white powder.
(c) Electric separation is a process that uses an electric field to separate charged particles.
Reverse osmosis is the most effective way to remove dissolved salts from water. It is used in a variety of applications, including drinking water purification, desalination, and wastewater treatment.