The correct answer is D) Phosgene gas may be formed if it comes in contact with hot metal. The reason this is the correct answer is that carbon tetrachloride is a halogenated compound, and when it is exposed to high heat or flames, it can break down and release phosgene gas, which is a highly toxic substance. Phosgene gas is extremely dangerous and can cause severe respiratory distress and other health issues. The other answer choices are incorrect because: A) Carbon tetrachloride is not flammable and will not burn rapidly; B) Water can be used to fight the fire, but it must be used with caution to avoid the formation of phosgene gas; and C) Carbon tetrachloride will not explode when exposed to a flame.