Which of the following is a correctly formatted Inmarsat-C address book entry for sending communications to a fax machine number (045) 334-5678 in Japan (voice country code 81)?

Correct Answer: Option C — 810453345678

International fax addressing requires the country code followed by the subscriber number, excluding domestic trunk prefixes like the leading zero. For Japan (81) and number 0453345678, the correct entry is 810453345678. Removing the leading zero is essential for successful international routing through the public switched telephone network.