Option 1: Amw is the designation for the tropical monsoon climate type. This climate is characterized by high temperatures throughout the year and a distinct wet and dry season. It is not the best suited to describe the climate of the western fringe of Rajasthan as it does not account for the arid and desert conditions.

Option 2: Aw is the designation for the tropical savanna climate type. This climate is characterized by high temperatures throughout the year and distinct wet and dry seasons. While there may be some similarities between Aw and the climate of the western fringe of Rajasthan, Aw does not account for the aridity and desert conditions that are characteristic of the region.

Option 3: Bwhw is the designation for the hot desert climate type with a winter wet season. This climate is best suited to describe the climate of the western fringe of Rajasthan. It accurately captures the arid conditions and the occasional rainfall during the winter season in the region.

Option 4: Cwg is the designation for the temperate climate with dry winters and cool summers. This climate type is not suitable to describe the climate of the western fringe of Rajasthan as it does not account for the high temperatures and arid conditions of the region.

Overall, option 3 (Bwhw) is the