Concept:Frost action is the weathering process in which water trapped in rock cracks freezes, expands, and breaks the rock apart.
Explanation:For frost action to occur, temperatures must frequently pass around the freezing point,
0∘C, so water can alternately freeze and thaw.
Equatorial regions are hot and humid all year, so frost action cannot take place there.
Monsoon and Mediterranean regions have mild or warm climates, where frost is limited to short winter periods or very high altitudes.
In contrast, cool temperate regions experience regular freezing temperatures; at higher elevations and in permafrost areas, frost action continues throughout the year.
Hence, cool temperate is the only region where weathering by frost action can operate all year round.
Answer:A. cool temperate