What must be included on a placard when transporting hazardous materials in a multi-trailer setup?

Answer: C — Specific identification of hazardous contents

When transporting hazardous materials in a multi-trailer setup, it is essential to include specific identification of the hazardous contents on the placard. This is a critical safety measure designed to inform emergency responders and others about the nature of the materials being transported in case of an incident or spill. By clearly identifying the type of hazardous materials being carried, the placard helps ensure that proper emergency procedures can be initiated quickly, thereby minimizing risks to human safety and the environment. In contrast, other options, such as the trailer's license plate information, the driver's personal contact information, and general contents of the trailer, do not provide the necessary clarity regarding the specific hazardous conditions that could arise. These pieces of information may not aid in the immediate understanding of the dangers presented by the materials being transported, which is the primary purpose of hazardous material placarding. Thus, specifying the hazardous contents is not only a regulatory requirement but also a vital component of safe transportation practices.