The west coast of India receives more rainfall from the southwest monsoon than the east coast primarily because of the Western Ghats. Option 2 is correct because the Western Ghats act as a barrier and obstruct the movement of winds. These winds are forced to rise when they encounter the Western Ghats, causing them to cool and condense, leading to rainfall. On the other hand, the Eastern Ghats, mentioned in option 4, extend parallel to the wind direction and do not obstruct the winds in the same way. Option 1, stating that the west coast is straight while the east coast is not, is not relevant to the difference in rainfall. Option 3, suggesting that the east coast is broader, does not explain the difference in rainfall patterns.