Step 1: Analyze the geographical locations. The question specifies trade between the North-East USA (e.g., ports like New York, Boston) and Western Europe (e.g., ports like London, Rotterdam, Hamburg).
Step 2: Evaluate the sea routes. The most direct and logical sea route connecting these two highly industrialized regions is across the North Atlantic Ocean. This is historically one of the busiest and most important shipping lanes in the world. The other routes are geographically incorrect for this trade link.