This question has options. Select from options: Read this fact: "natural gas is a source of heat by burning"

Now answer this question: "If someone wants to use a natural gas in order to assist something necessary, they can"

Select from the following.
I. use it to bathe in;
II. eat it to die quickly;
III. freeze it to make ice cubes;
IV. ignite it to warm their body;
IV.