CDL Test Trick: Don’t Get This Hazmat Question Wrong! To properly placard a vehicle, you must know: A. Materials hazard class. B the amount being shipped. C amount of all hazardous materials of all classes on the vehicle D all the above. The correct answer is D. All of the above! Want to know why? Check out our Hazmat Endorsement Questions and Answers video on YouTube. Want to get your CDL license?! Driving Academy will help: Visit https://www.cdldrivingacademy.com/?utm_medium=social&utm_id=1211