The correct answer is D) All of the above. Penetrations and openings in watertight bulkheads on small passenger vessels less than 100 gross tons must meet the following requirements: 1) They must not contain sluice valves that allow water to flow freely from one watertight compartment to another, as this would compromise the watertight integrity. 2) They must have some means to make them watertight, such as watertight doors or hatches, to maintain the vessel's watertight subdivisions. 3) They should be kept as high and as far inboard as possible to reduce the risk of water ingress in the event of damage. All three of these requirements work together to ensure the watertight bulkheads can effectively contain flooding and prevent the progressive flooding of the vessel, which is critical for small passenger vessel safety.