Correct Option
The correct option is West coast of Sumatra.
Explanation
The width of the continental shelf varies significantly depending on the geological structure of the coast. Continental shelves are generally wider along passive margins (stable coasts) and very narrow or absent along active margins (coasts near plate boundaries or deep-sea trenches).
Option Analysis
- Siberian Coast: Incorrect. The Arctic Ocean, specifically along the Siberian coast, possesses the widest continental shelf in the world, extending up to 1,500 km in width.
- West coast of Sumatra: Correct. This coast is located near a convergent plate boundary where the Indo-Australian Plate subducts beneath the Eurasian Plate (Sunda Plate). The presence of the deep Sunda Trench parallel to the coast results in a continental shelf that is extremely narrow or almost absent.
- Eastern coast of North America: Incorrect. This is a classic example of a passive continental margin. It is geologically stable and features a relatively wide and well-developed continental shelf.
- North Sea: Incorrect. The North Sea is a shallow epicontinental sea located entirely upon the European continental shelf. Consequently, the shelf here is extensive rather than narrow.
Key Takeaway: Continental shelves are narrowest where high mountains are close to the coast or where deep-sea trenches are present (e.g., coasts of Chile and Sumatra). They are widest along low-lying, stable coasts (e.g., Siberian Shelf).