Which of the following statements concerning Inmarsat geostationary satellites is true?

Correct Answer: Option C — They provide coverage to vessels in nearly all of the world's navigable waters.

Inmarsat satellites are positioned in geostationary orbit (GEO) above the equator. While they do not cover the extreme polar regions (above approximately 76 degrees latitude), they provide reliable, continuous coverage to vessels across nearly all navigable waters, fulfilling the primary requirements for GMDSS global maritime safety communications.