Why does the western coast receive heavy rainfall while the eastern coast shows a different seasonal pattern?

Correct answer: The western coast is affected by Western Ghats and Arabian Sea branch while the eastern coast may be affected by retreating monsoon

The direct answer is B: the western coast is strongly affected by the Arabian Sea branch of the southwest monsoon and the Western Ghats, while the eastern coast can receive an important share of rain from the retreating or northeast monsoon. Rainfall depends on wind direction, moisture source, relief, and season. Moist southwest monsoon winds from the Arabian Sea strike the Western Ghats on the western side of India. The mountains force the moist air to rise, causing heavy orographic rainfall on the windward side. After crossing the mountains, the air is drier, so some interior areas receive less rain. The eastern coast has a different seasonal pattern because during the retreating monsoon, winds associated with the northeast monsoon can collect moisture over the Bay of Bengal and bring rain to parts of the southeast coast. Option A is wrong because the two coasts are not controlled by exactly the same branch and timing. Option B is correct because it identifies both the Western Ghats-Arabian Sea influence and retreating-monsoon influence. Option C is wrong because the eastern coast is part of India. Option D is wrong because the western coast lies beside the Arabian Sea. Memory cue: west coast—Arabian Sea plus Ghats; southeast coast—retreating monsoon and Bay of Bengal.