Which peak marks the north-western end of the Great Himalaya?

The correct option is Nanga Parbat.

To understand why Nanga Parbat marks the north-western end of the Great Himalayas, let us look at the structure and span of this mountain range:
1. Geographical Extent: The Great Himalayas, also known as the Himadri, form the northernmost and tallest range of the Himalayan mountain system. This range forms an arc that stretches across a vast distance of approximately 2,400 kilometers.
2. North-Western Anchor: In the north-west, this massive arc terminates abruptly at the peak of Nanga Parbat (rising to an elevation of 8,126 meters), which is located in Pakistan-administered Gilgit-Baltistan near the Indus River bend.
3. Eastern Anchor: In the east, the range terminates at the peak of Namcha Barwa (7,782 meters), located in the Tibet region near the Brahmaputra River (Tsangpo) bend.

Let us briefly review the other options to understand why they do not mark the north-western end:
- Mount Everest: Located on the border between Nepal and China (Tibet), it lies in the central part of the Great Himalayas, not at its north-western boundary.
- Kanchenjunga: Situated on the border between India (Sikkim) and Nepal, it is located in the eastern-central region of the Great Himalayas.
- Namcha Barwa: As noted above, this peak marks the easternmost termination point of the Great Himalayas, opposite to the north-western end.

Therefore, Nanga Parbat is the correct peak marking the north-western end of the Great Himalayan range.