What is the international calling and distress channel found on all VHF-FM equipped drilling rigs?

Correct Answer: Option C — Channel 16

VHF Channel 16 (156.8 MHz) is the internationally designated frequency for distress, safety, and calling. All vessels, including drilling rigs equipped with VHF-FM radios, are required to monitor this channel to ensure immediate response to distress alerts and to facilitate initial contact between stations at sea.