_________ are used for converting saline or brackish water into pure distilled water.

The correct answer is: B. Solar desalination systems.

Solar desalination systems are used to convert saline or brackish water into pure distilled water. They use the sun’s energy to evaporate the water, and then condense the vapor back into pure water.

Photo voltaic cells (A) convert sunlight into electricity. Solar cookers (C) use the sun’s heat to cook food. Solar water-heating (D) uses the sun’s heat to warm water.