Which action should the GMDSS radio operator take in a distress situation when embarking in survival craft?

Correct Answer: Option C — Switch on EPIRB and SART immediately and leave on.

Upon abandoning ship, the GMDSS radio operator must ensure that the SART and EPIRB are switched on and operational. These devices are critical for locating the survival craft; the SART provides a radar target, while the EPIRB transmits the distress signal via satellite, as required by SOLAS.