What was the chief duty of zhou kings?

(d) corporate responsibility.

Explanation:

This is the kind of obligation a company has, to be more conscious on the kind of impact they have to; society, economy, and environment, as a whole.

Fair traetment of employees by ChemCo, is an example of corporate responsibility over the welfare of employees.

The move to make minimal environmental impact is a responsibility that the company undertakes as a means to conserve the environment and hence, corporate responsibility.