Where must placards be placed on a vehicle?

Answer: C — On all four sides

Placards are critical for identifying hazardous materials that a vehicle may be carrying. According to regulations, they must be displayed on all four sides of the vehicle. This ensures visibility from all angles, allowing first responders and others nearby to quickly recognize the potential hazards associated with the cargo. Proper placement is essential for safety and compliance with transport regulations, as it provides crucial information in case of an emergency or accident. By adhering to this requirement, drivers and carriers can help promote safety for everyone on the road.