Fact 1: Heating salt water causes the water to evaporate while the salt remains. Fact 2: Evaporation of the water leaves the salt on the surface. Given the two facts above, heating salt water leaves the salt where?

Pick your answer from:
(a). solid, liquid, gas;
(b). on the surface;
(c). Solutions;
(d). epidermis and dermis;
(e). lowered energy cost;
(f). energy barrier;
(g). an object;
(h). near the shoreline;
Answer:
(b).