Which of the following is a correctly formatted Inmarsat-C address book entry for sending TELEX communications to a vessel in the POR?

Correct Answer: Option A — 582436559121

The 582 prefix denotes the Pacific Ocean Region (POR) for Inmarsat-C TELEX communications. The sequence 582436559121 follows the established addressing convention for this region, ensuring the message is routed through the appropriate Land Earth Station serving the POR to reach the intended vessel or terminal.