What is the minimum requirement of a GMDSS radio operator?

Correct Answer: Option C — GMDSS Radio Operator license.

The GMDSS Radio Operator license is the standalone credential required by the FCC for personnel operating GMDSS-compliant ship stations. It confirms the operator has met the necessary training standards for distress alerting, watchkeeping, and general communications, satisfying all legal requirements for operating compulsory GMDSS radio equipment.