How can evaporation fog form when cold air moves over a warm water surface?

Correct answer: Warm water supplies moisture and cold air saturates quickly

Correct answer: A. Warm water supplies heat and adds water vapour to the air immediately above its surface. When colder air moves across that water, the added vapour mixes into air that has a lower capacity to hold water vapour. The air therefore approaches saturation quickly. Some of the vapour then condenses into tiny suspended droplets, producing evaporation fog, also called steam fog in suitable examples. B is wrong because cold air has a limited, not infinite, capacity for water vapour. C is the opposite of reality: warm water can provide substantial vapour. D is impossible because fog consists of tiny water droplets or, in cold conditions, ice particles. The key sequence is warm water, moisture addition, cooling or mixing, saturation, and condensation. Memory cue: “Warm surface feeds moisture; cold air turns it visible.”