Answer: Code of ethics
Explanation: Code of ethics in professional field or organizational field is referred as the principles that are responsible for the correct conduct of business organization by governing its functioning and decisions.It is a major key of business field as it maintains right practices,handles issues, provides guidance etc.
Other options are incorrect because business ethics cannot be implemented as principle for the governing the organization working and employees. Common good practice and approach is the basic good conduct and approaching but these factors don't govern the business.