Option 2, "Nanda Devi - Kumaon Himalaya," is correctly matched because Nanda Devi is indeed situated in the Kumaon region of the Himalayas, making it one of the prominent peaks in that specific range. Conversely, Namcha Barwa is located in the eastern Himalayas, specifically in Arunachal Pradesh, rather than in the Garhwal Himalaya, and Nokrek is located in the Garo Hills of Meghalaya, not in Sikkim. This distinction highlights the regional classification of Himalayan ranges and peaks, which is essential knowledge for understanding the geography of India as per the UPSC syllabus.