A vehicle contains 500 pounds each of explosives A and B. What type of placards must you use?

In this scenario, the correct choice of placards is essential due to the specific regulations governing the transport of hazardous materials. When transporting explosives, the type of placarding required depends on the classification and amount of the explosives being transported.

Since the load consists of explosives A and B, both of which are classified as explosives under the Hazardous Materials Regulations (HMR), the placarding needs to reflect the specific type of explosives being handled. Using "Explosives A" placards is accurate as they provide clear identification of the type of explosive material being transported, aligning with the HMR requirements for placarding based on the type of substance.

The selection of "Dangerous" placards or "Blasting agents" placards would not accurately convey the specific nature of the explosives being transported, as these options refer to broader categories or secondary classifications that do not indicate the exact type of explosive you are dealing with. Therefore, identifying the load correctly with "Explosives A" placards ensures compliance with safety regulations and proper identification for emergency responders.