What is the requirement for placing a radioactive Yellow II moisture density gauge?

The correct choice indicates that no placards are needed when placing a radioactive Yellow II moisture density gauge. This is because the Yellow II designation refers to a specific category of radioactive materials that are not deemed to be overly hazardous compared to other classifications. As a result, regulatory requirements for signage and placarding differ based on the level of radiation risk.

In practice, a Yellow II radioactive gauge is generally used in environments where trained personnel are aware of the hazards associated with the use of such equipment. Since these gauges are designed to be safely operated by trained individuals, the absence of placarding is acceptable in a controlled setting.

Additionally, regulatory frameworks typically dictate that placards are required for higher-risk categories or when transport or storage conditions warrant additional hazard communication. Since Yellow II materials pose a lower risk, this less stringent requirement aligns with safety standards while still ensuring that users are adequately trained to handle the device properly.