Which concept, brought forward by Locke, represented a shift in thinking about the role of government?

A. Citizens must support monarchs because they were chosen by God and cannot be displaced by man.
B. Royalty has a responsibility to serve the wealthy before the poor because the wealthy pay more taxes.
C. The government's duty is to maintain order even at the expense of the rights of the people.
D. A government exists to protect the citizens, and they have a responsibility to change it if it fails to do so.