As routine maintenance, the bilge manifold valves are periodically removed and examined. Prior to resecuring the valve bonnets, the valve __________.

Correct Answer: Option D — all of the above

Routine maintenance of bilge manifold valves ensures system integrity under 46 CFR Subchapter F. Lapping seats, replacing torn gaskets, and renewing hardened packing are essential to prevent internal leakage and ensure positive shut-off, which is critical for maintaining vessel watertight integrity and preventing accidental pollution during bilge pumping operations.