One of the training modules that Anna uses when training Best Insurance Agency's new employees is about ethics. She explains that ethics can be defined in many ways. She reviews all of the following definitions EXCEPT

a. the discipline dealing with what is good and bad and with moral duty and obligation.
b. a set of politically correct values.
c. the principles of conduct governing an individual or a group.
d. a set of moral principles: a theory or system of moral values.