How must a shipper label hazardous materials?

Answer: B — With a diamond-shaped label on the package or product

The requirement for labeling hazardous materials is to use a diamond-shaped label on the package or product. This standardized labeling format is crucial as it instantly conveys critical information about the hazards associated with the materials being transported. The diamond shape is recognizable and universally understood within the transport industry, indicating both the nature of the hazard and the proper precautions that must be taken. This labeling helps ensure safety during handling, transport, and storage by providing immediate visibility of the risks involved. While stamping, using stickers, or electronic documentation may play a role in the overall identification and documentation of hazardous materials, these methods do not replace the necessity for the specific and recognizable diamond-shaped labels. Labels must be durable, resistant to weather, and positioned so that they are clearly visible during transport. Thus, the diamond-shaped label is the correct and legally mandated form of labeling for hazardous materials.