What differentiates advection fog from radiation fog and steam fog?

Advection fog is primarily characterized by the horizontal movement of warm, moist air over a cooler surface, typically occurring in coastal regions where warm moist air from the ocean moves over cooler land. This process leads to the cooling of that air mass and the formation of fog.

In contrast, radiation fog develops under calm, clear conditions at night when the land quickly loses heat through radiation cooling. This type of fog is usually concentrated over land, especially in low-lying areas.

The differentiation provided in the selected answer reflects the geographic and environmental contexts where each fog type typically forms, emphasizing how advection fog commonly appears in coastal areas due to oceanic influence, while radiation fog is a result of temperature drops at night over land.

The other options do not accurately describe the distinct conditions that lead to the formation of these types of fog. For instance, the claim about steam fog forming in deserts does not align with its actual occurrence, which is more associated with bodies of warm water mixing with cooler air. Additionally, radiation fog can develop in the early morning near land as well, not strictly at night, and advection fog can indeed form at various times depending on the air movement.