The correct answer is D. on.
The sentence “Look, that car’s on fire” is a statement about the location of the fire. The fire is on the car, not in the car or through the car. The other options are not correct because they do not describe the location of the fire.
Option A, through, is incorrect because it suggests that the fire is passing through the car. This is not the case, as the fire is only located on the car.
Option B, with, is incorrect because it suggests that the car is carrying the fire. This is not the case, as the car is not moving and the fire is not being transported.
Option C, into, is incorrect because it suggests that the fire is entering the car. This is not the case, as the fire is only located on the car.
Option D, on, is the correct answer because it describes the location of the fire. The fire is on the car, not in the car or through the car.