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 D — All may be correct, depending on the Inmarsat system addressed.

Inmarsat-C addressing for TELEX is highly dependent on the specific Land Earth Station and the service provider's routing protocols. Because different providers may utilize varying formats or prefixes for the same region, all listed options could potentially be correct depending on the specific system configuration being addressed.