Option B is correct because the context clearly states that the Big Trunk Route has the greatest foreign trade in the world, with one-fourth of the world's foreign trade moving on this route. It is described as 'the busiest in the world' and 'both the coasts have highly advanced ports and harbour facilities.' These characteristics match the North Atlantic Ocean route, which connects the highly industrialized regions of Western Europe and Eastern North America. The other routes mentioned in the context (Cape of Good Hope Sea Route and Southern Atlantic Sea Route) are described separately, indicating they are different from the Big Trunk Route.