What is NOT required of the cargo tank venting on a tank barge carrying grade A liquids?

Correct Answer: Option C — The diameter of the vent must be greater than 4 inches in diameter.

USCG regulations for tank barge Grade A venting require individual tank vents, appropriate height above deck, and P/V valves or flame screens, but do not mandate a minimum vent diameter exceeding 4 inches universally across all barge configurations.