Explanation

The shortest air route is generally determined by great-circle navigation, which does not necessarily follow a major body of water like the Atlantic. Option A (Over the South Pole) and B (Over the North Pole) are highly unlikely or impossible routes for commercial aviation due to extreme conditions or lack of direct path. Option C (Over the Atlantic Ocean) is incorrect because the shortest route will likely pass over landmasses or follow a more direct great-circle arc that avoids crossing the entire ocean if possible, making D the most accurate choice.