Final answer:
a. 1.
While the specific number of required fire extinguishers may vary by jurisdiction, common safety regulations require at least one to be present in vehicles transporting explosives. Specific safety guidelines must be consulted to determine the exact number required.
Step-by-step explanation:
In the context of safety regulations for vehicles transporting hazardous materials such as explosives, regulations typically require that such vehicles be equipped with fire extinguishers to deal with any potential incidents. While the specific number of fire extinguishers required may vary by jurisdiction and the type or class of explosives being transported, a commonly mandated minimum is that at least one fire extinguisher should be present and ready for immediate use. However, based on provided references which does not directly answer the question, it's unclear what the exact required number is without citing specific regional or national safety guidelines. The general practice is to follow the strictest safety measures possible, which can mean equipping vehicles with multiple fire extinguishers to cover different potential types of fires that may occur.