The correct option is Coastal plain and windward side.
Explanation
The phenomenon described is known as Orographic or Relief Rainfall. This type of rainfall occurs when moist air masses are forced to rise over a topographic barrier, such as a mountain range, that lies across the path of the wind.
Detailed Analysis:
- Windward Side and Coastal Plain: When mountains run parallel to the coast, they act as a barrier to moisture-laden winds blowing from the sea. As the air strikes the mountain, it is forced to ascend. As the air rises, it expands and cools (adiabatic cooling). This cooling leads to condensation and the formation of clouds, resulting in heavy precipitation on the side of the mountain facing the wind (the windward side) and the adjacent coastal plain.
- Leeward Side (Rain Shadow Area): After crossing the mountain peak, the air descends on the opposite side (the leeward side). As it descends, the air is compressed and warms up (adiabatic warming). This increase in temperature reduces the relative humidity and the air's ability to hold moisture increases, preventing precipitation. Consequently, this region remains dry and is referred to as the rain shadow area.
Therefore, the rainfall is significantly greater on the coastal plain and the windward side compared to the interior or leeward side.
Key Takeaway:
In orographic rainfall, the windward side receives heavy precipitation due to the ascent and cooling of moist air, while the leeward side remains dry due to the descent and warming of the air.