Correct Response: D. In meteorology, advection is the bulk movement of energy or mass horizontally through the atmosphere, and advection fog is fog that forms when relatively warm moist air flows over a colder surface such as the ocean. When cold air becomes trapped beneath warm air (A), an inversion results (and not advection fog). Hot, relatively dry air can produce fog (B) if it is cooled below its dew point. This type of fog is called radiation fog because it forms in place as the ground radiates its heat and cools down. When cool, moist air flows down a mountain (C), the pressure on the parcel of air increases, reducing its volume and increasing its temperature. This type of adiabatic warming causes the relative humidity of the parcel to decrease and would not produce fog.
