"Churning" Is a Term Used to Describe What Ethical Offense

"Churning" is a term used to describe what ethical offense?

A) trading one product or service for another
B) a public relations agency violating the confidence of a client
C) a public relations agency creating unnecessary work or exaggerating the amount of staff time involved in a project in order to pad the client's bill
D) accepting kickbacks or commissions for referrals
E) a public relations agency promising results to the client that are beyond the agency's control