Explanations:The northeastern states of India, including Arunachal Pradesh, Assam, and Sikkim, are characterized by their heavy rainfall. This is due to several geographical and climatic factors. The region is located in the eastern Himalayan range, which influences the monsoon patterns and results in significant precipitation. The monsoon season, which typically occurs from June to September, brings substantial rainfall to these areas, making them some of the wettest regions in India.
Arunachal Pradesh, located in the eastern Himalayas, receives heavy rainfall due to its mountainous terrain and the influence of the monsoon winds. The state's topography, with its high mountains and valleys, creates a favorable environment for precipitation. The Brahmaputra River, which flows through the state, also contributes to the moisture in the region.
Assam, another northeastern state, is known for its high rainfall, particularly in the Brahmaputra Valley. The state's location and the presence of the Brahmaputra River make it a region of heavy rainfall. The monsoon winds bring moisture from the Bay of Bengal, leading to significant precipitation in Assam.
Sikkim, situated in the eastern Himalayas, is another state with heavy rainfall. The state's mountainous terrain and the influence of the monsoon winds result in substantial precipitation. The Kanchenjunga range, the third-highest peak in the world, plays a significant role in the region's climatic conditions, contributing to the heavy rainfall.
Therefore, all three states—Arunachal Pradesh, Assam, and Sikkim—are areas of heavy rainfall, making option D the correct answer. The northeastern states collectively receive significant precipitation, particularly during the monsoon season, due to their geographical and climatic conditions.