Connecting to trade routes can depend on several factors such as geographical location, infrastructure, and existing trade agreements. Generally speaking, North America (option c) might be considered more difficult to connect to via trade routes compared to the other continents. This is due to its relative distance from many major trade routes that are more centralized in Europe, Asia, and Africa, as well as its reliance on a few key trade partners. However, modern logistics and trade networks have improved access to North America significantly.
That said, specific regions within these continents may present different challenges, and a thorough analysis of trade infrastructure would be necessary for a definitive answer.