Which of the following does not belong to the category of dangerous goods?

• A. Explosives
• B. Toxic substances
• C. Radioactive substances
• D. Biohazard substances

Answer: (D)

Dangerous goods are organized into official classes used by transport rules, with specific names for each category. Explosives and radioactive substances are clearly recognized classes on their own, and toxic substances fall under a defined class as well. The term “biohazard substances” isn’t listed as a separate official class in these regulations. It’s a general label for biological risks, but it isn’t named as a distinct category of dangerous goods in the classification system. So, among the options, biohazard substances do not constitute a separate formal dangerous goods category, making it the best answer for what does not belong.