Answer: C. An exception based on public policy.
Explanation: Flem reporting to state official about his company Glo inc illegally shipping unsafe goods was a "public good". Flem can sue his firm for firing him on the base of employment at will rule, "exception based on public policy"
Exception based on public policy is a rule to exception on employment at will rule. In this exception, an employer of labor can not fire an employee if it is in violation of the doctrine of public policy of the state.