Edgar is stranded on an island surrounded by an ocean of salt water. He is thirsty, but he knows that it is a bad idea to drink salt water.
 How could Edgar separate the salt out of the salt-water mixture?
 A. 
 pour the mixture through a screen
 B. 
 use chromatography
 C. 
 evaporate off the water
 D. 
 use a magnet to attract the salt