Which of the following statements with regard to the continental shelf is NOT correct ?

The correct answer is C because it inaccurately describes the topography of the continental shelf.

• Statement C is NOT correct: The continental shelf is defined as a gently sloping platform (gradient of 1° or less). It does not "have abrupt falls"; rather, it ends at the shelf break, where the gradient increases sharply to form the continental slope. The "abrupt fall" is a characteristic of the slope, not the shelf.
• Statement A is correct: Along active plate boundaries (convergent margins like the coast of Chile), continental shelves are often extremely narrow or virtually absent due to the presence of deep-sea trenches close to the shore.
• Statements B and D are correct: Shelves are regions of heavy sediment deposition from rivers and are rich fishing grounds due to sunlight penetration and plankton growth in shallow waters.