On international voyages, tank ships of 500 gross tons or more, are required to have facilities to enable a connection on each side of the ship for which piece of equipment represented in illustration D039SA below?

Correct Answer: Option C — 53

SOLAS Chapter II-2 requires international voyages for tank ships of 500 gross tonnage and above to maintain an international shore connection, designated by symbol 53. This standardized flange enables shoreside fire mains to connect directly to the ship's fire system regardless of national thread standards.