What does a DSC control unit doWhen a DSC message is received?

A、WhenreceivingDSCmessageotherthanAdistress,urgencyandsafetycall,theControlunitisabletoprovideforanAutomatictransmissionacknowledgingThecallreceived.
B、TheinformationcontainedintheDSCMessageisdecodedanddisplayedontheFrontpanelandmaybestoredinanInternalmemory.
C、AnaudioalarmsoundswhenaDSCMessageisreceived.
D、Allofthese