Final answer:
When fighting a vehicle fire, you should not open the hood if the fire is underneath it and avoid using water on gasoline or oil fires, meaning option d. a. and b. are correct.
Step-by-step explanation:
When attempting to fight a fire in your vehicle, the correct actions include: a. Avoid opening the hood if the fire is under it, as this can introduce fresh oxygen and cause the fire to flare up; and b. Avoid using water on gasoline or oil fires, as water can spread the flammable liquids, making the fire worse. Therefore, the answer to this question is d. a. and b. are correct.
It's important to note that using too much extinguishing agent can be hazardous and wasteful, so use extinguishers as directed, aiming at the base of the fire. Always prioritize safety and be ready to call professionals if the situation escalates beyond your control.