The correct option is D - C
The Mongols valued their trade relations with neighboring countries, and maintained their policy of opening to trade during their conquests and expansion.
All merchants and ambassadors who had the proper documentation and authorization, were protected while traveling through their domains, which is why the trade in land, from the Mediterranean to China, was intensified through well-maintained and busy routes as there was no fear of The bandits. However, the Mongols did not have much influence on maritime trade.