The diagram given below shows the schematic relations of temperature and precipitation of tropical climatic type over land : Arrange the climatic types in the correct sequence from left to right: 1. Monsoon tropics 2. Wet and dry tropics 3. Arid and semiarid 4. Rainy tropics Select the correct answer using the code given below.

The diagram likely depicts the climatic gradient across a hypothetical continent in the tropical latitudes (10°–30°). In this region, a distinct moisture gradient exists from west to east due to the trade winds:

• Left (West Margin): dominated by high pressure and cold currents, resulting in Arid and Semiarid (3) climates (Deserts).
• Center (Interior): transition zone with seasonal rainfall, corresponding to Wet and Dry Tropics (2) or Savanna.
• Right (East Margin): exposed to onshore trade winds and warm currents, leading to high rainfall regions like Monsoon Tropics (1) and Rainy Tropics (4).

Thus, the correct sequence from left (dry) to right (wet) is 3 → 2 → 1 → 4.