What Is Necessary in Order to Authorize Release of Medical

What is necessary in order to authorize release of medical information to an insurance carrier?

A) A verbal agreement between the patient and the doctor is necessary. 
B) A medical release from the patient is needed. 
C) A handshake between the patient and the doctor is all that is necessary. 
D) Authorization is never required to release medical information. 
E) Physicians never have to share medical information.