What number would place an automatic TELEX call to the subscriber number of 123456 using an Inmarsat-B SES in the Western Atlantic?

• A. 00230123456+
• B. 00230123456#
• C. 0012131234567#
• D. 001 213 1234567+

Answer: (A)

To place an automatic TELEX call to the subscriber number of 123456 using an Inmarsat-B SES in the Western Atlantic, the correct number format incorporates the appropriate country codes and dialing conventions.

The choice that includes the correct format starts with "00," which indicates the international access code required to initiate the call from a location outside of the Western Atlantic region. Following this, "23" is the country code assigned to the United States and Canada for TELEX calls, and "0123456" represents the subscriber number you intend to reach.

The addition of the "+" at the end of the choice signifies that the call is being completed, as is standard in international dialing conventions, especially when connecting to digital systems like TELEX. The use of a "+" often indicates that you can expect a completion of the call, ensuring that all necessary protocol-specific parameters are being met.

This precise combination of numbers adheres to the required dialing format for making an automatic TELEX call successfully through Inmarsat-B SES, making this answer the appropriate choice for the question posed.