If a frost layer first melts in sunlight and then disappears, what is the correct process sequence?

Correct answer: Melting followed by evaporation

Answer: B. Frost is frozen water, usually ice crystals or a thin ice deposit on a cold surface. When sunlight supplies heat, the ice first changes from solid to liquid water; this phase change is melting. If the liquid water then changes into water vapour and enters the air, the second process is evaporation. Thus the sequence is melting followed by evaporation. Option A is wrong because condensation produces liquid or solid water from vapour, while erosion is the removal of earth materials and is not the relevant process here. Option C reverses the order and introduces snowfall without evidence. Option D combines unrelated processes. A frost layer may sometimes disappear by direct sublimation, but the question specifically says it first melts, so melting then evaporation is the intended sequence. Memory cue: solid to liquid is melting; liquid to gas is evaporation.