Explanation: INMARSAT satellites are geostationary, meaning they orbit Earth above the equator at an altitude that causes them to appear stationary from the ground. This fixed position allows them to provide continuous coverage over a wide geographical area. Option C is correct because, while geostationary satellites cannot cover the extreme polar regions, the INMARSAT constellation strategically positions its satellites to ensure comprehensive coverage across nearly all of the world's oceans and navigable waters. This is crucial for maritime safety and communication services. Option A is incorrect because geostationary satellites are by definition in an equatorial orbit, not a polar orbit. Polar orbits are used by some non-geostationary satellite systems to achieve pole-to-pole coverage. Option B is incorrect because, although INMARSAT satellites are in an equatorial orbit, geostationary satellites cannot provide "true global coverage" as they cannot 'see' the areas near the poles. Option D is incorrect. Vessels, including those in equatorial waters, can often see and utilize multiple INMARSAT satellites, selecting the one with the best signal or capacity, rather than being restricted to a single satellite.