To establish a communication channel for the telex service in the INMARSAT-Aterminal, you should first().
A、establish a communication channel from the CES, via the International Telex Network to the final destination
B、set up a communication channel from your SES, via a satellite, to a CES within your ocean region
C、set up a channel directly to the addressee at the destination
D、establish a channel from your terminal , via the International Telex Network to a CES within your ocean region