The best example of the principle of checks and balances among the options provided is:
c. courts release a person charged with violating a law that is considered unconstitutional.
This option exemplifies checks and balances because it involves the judiciary exercising its power to review and potentially overturn actions taken by the legislative branch (law-making) if those actions are found to conflict with the Constitution. This process ensures that no branch of government exceeds its authority or infringes on individual rights.