On offshore drilling units each ring life buoy must be marked, in a contrasting color, with the unit's __________.

Correct Answer: Option C — name and port of registry

46 CFR 108.649 mandates that each ring life buoy on a MODU must be plainly marked in a contrasting color with the unit's name and port of registry. This identification ensures that life-saving equipment can be traced back to the specific vessel during recovery or post-incident investigations.