I think the correct answer would be the first option. Chemical weathering would be most effective in a warm, humid climate. It is a type of erosion which is caused by chemical reaction that happens naturally in the environment. It is usually caused from the reaction of the minerals found in rocks with the rain water. These reactions happen when the rain water contains acidic components. Also, its occurrence would be more fast in places where there is high temperature or in warm regions specifically for hydrolysis and oxidation reactions. For the reactions to happen, the presence of water is very important so it most likely in humid places.
