The correct option is The Siberian shelf in the Arctic Ocean.
Explanation
The continental shelf is the submerged, gently sloping extension of a continent. The width of a continental shelf varies drastically depending on whether the coast is a passive margin (stable, wide shelves) or an active margin (tectonically active, narrow shelves).
- The coast of Chile is incorrect: The coast of Chile is an active continental margin where the Nazca Plate subducts beneath the South American Plate. Active margins are characterized by deep trenches and extremely narrow or non-existent continental shelves.
- The west coast of Sumatra is incorrect: The west coast of Sumatra lies along a convergent boundary associated with the Sunda Trench. Like the Chilean coast, the continental shelf here is narrow due to the proximity of the subduction zone.
- The Siberian shelf in the Arctic Ocean is correct: The Siberian Shelf in the Arctic Ocean is the largest continental shelf in the world. It extends approximately 1,500 kilometers in width from the coast of Russia. The Arctic Ocean is surrounded by extensive passive margins, resulting in very broad shelves.
- The eastern coast of North America is incorrect: The eastern coast of North America is a passive margin and features a relatively wide continental shelf compared to the Pacific coast. However, it is significantly narrower than the Siberian Shelf.
Key Takeaway: Continental shelves are widest along passive margins and narrowest along active margins. The Siberian Shelf in the Arctic Ocean holds the record for the greatest width globally.