Answer:
C
Step-by-step explanation:
A was established because when trade thrives, it's easier for disease to travel.
B was established because an important aspect of "Pax Mongolica" was the Mongols creating a safer trade route so people could trade faster, safer and therefore this results in the growth of trade.
C. Pax Mongolica doesn't have much to do with China
D. Cultural diffusion results in innovations + ideas travelling when trade is thriving