Which of the Following Is the Best Definition of the Term

Which of the following is the best definition of the term due diligence?

A) the expected standard of conduct that requires employers to take every reasonable precaution to ensure safety
B) the voluntary standard of conduct that requires employees to take every reasonable precaution to ensure safety
C) the expected standard of conduct that requires employers to protect the public
D) the expected standards of conduct that require government to ensure employers comply with legislation