What is usually the first step for a GMDSS Radio Operator to take when initiating a distress priority message via INMARSAT?

A
Dialing the correct code on the telephone remote unit
B
Pressing a "distress button" on the equipment
C
Contacting the CES operator and announcing a distress condition is in existence
D
Contacting the CES operator using the radiotelephone distress procedure "Mayday"...etc.
E