Which statement best describes radiation fog?

Radiation fog is primarily associated with the cooling of the Earth's surface during the night. As the ground loses heat through radiation, the air close to the surface also cools. This cooling can cause the air to reach its dew point, where it can no longer hold all its moisture, leading to condensation and the formation of fog. This process is most effective on clear, calm nights when there is little wind to disrupt the cooling.

Other choices do not accurately represent how radiation fog forms. For instance, the first choice involves warm air moving over cooler surfaces, which typically describes advection fog rather than radiation fog. The second choice suggests formation during the day, which contradicts the nocturnal cooling process essential to radiation fog. Lastly, the fourth choice describes coastal fog, which is influenced by ocean breezes, typically associated with either advection or sea fog, rather than the stagnation and cooling that characterize radiation fog.