Answer:
D. Class D Rating
Step-by-step explanation:
The Class D rating in portable fire extinguisher ratings refers to fires involving burning metals and these metals tend to be flammable metals and therefore, requires specialist powder to be extinguised - this is determined on a case by case incident.
Because of the contents that make up different metals, the toxicity and the fume toxicity then has to be considered as the fumes produced from extinguishing the metal could be more harmful due to interacton of chemical reactions