What information is engraved on scuba tanks for identification?

The correct information engraved on scuba tanks for identification typically includes the date of the hydrostatic test, serial number, and type of material. The hydrostatic test date is crucial because it indicates when the tank was last tested for structural integrity and safety, ensuring that it can safely hold high-pressure gas. The serial number serves as a unique identifier for the tank, allowing for tracking of its manufacturing and service history. The type of material tells users what the tank is made of, which can affect its weight, buoyancy, and pressure rating.

While other options may mention important safety or operational details, they do not encompass the standardized identifiers universally required for scuba tanks. Safety certifications, dive instructor details, and other information are important for dive safety but are not typically engraved directly onto the tanks themselves.