Answer:
By preventing companies from doing serious damage to the
environment
Explanation:
That sounds like a citizen to me
While pax romana was a period which characterized a period of peace in the Roman empire where very little conquest was being done, perhaps a farmer who is selling his produce in Rome would be the correct answer - D.
As a farmer who would be selling his produce in Rome could signify a time where goods are abundant and he can safely sell his produce.