Which of the following two-way communications can be made through Inmarsat without charge?

Correct Answer: Option C — Distress traffic

Under IMO GMDSS requirements, Distress traffic is provided free of charge to the vessel. This policy ensures that mariners are not discouraged from initiating emergency communications due to potential costs. All Land Earth Stations are mandated to handle Distress alerts and subsequent traffic without billing the vessel in distress.