What is the correct procedure for leaving a voice mail?

A: Leave your name and tell the user you will call them back in the next hour or so B: Leave the date, time and your name, SLA requirements, detailed information regarding the Service Desk process for this type of incident and advise them to do nothing until they hear from you again C: Leave your name, date and time, contact number, incident number, the reason for your call and any action required of the user D: Leave the user with the message that the service desk tried to call them, give the time and date of the call, advise them that there has been a development with their incident