Answer:
Correct answer is expansion of trade across Eurasia.
Step-by-step explanation:
First option is correct as during Mongolian rule, trade on the famous Silk road was flourishing that led to better trade connections between Europe and Asia. This was the case until the Ottomans started controlling that route.
Second option is not correct as this never happened in this period.
Third option is not correct as more and more people were included in trading and similar labors, especially crafts.
Fourth option is not correct as Mongols didn't change their habits.