What steps did chinese emperors take to reduce foreign influence in china? check all that apply.

Assuming that this is referring to the same list of options that was posted before with this question, the correct two responses would be that they practiced a policy of "economic isolation" and placed limits on the amount of ports that could participate in trade. 

The answer is letter c, specialization increase the demand for product. It is because specialization focuses more on the products that are being produced in which they provide greater quality for the consumers in which promotes its product efficiency.