Answer: A. I,II and III
Explanation:
Let's describe the situation in a simplified way.
First remember, in ambient temperature, the candle is in solid form.
As you light the candle, the region of the candle near the flame suffers an increase in energy, caused by the heat of the flame. As you know, when we give enough heat to a solid, it will change of phase, from solid to liquid, and this is why the candle melts. Now, this change of phase is due to the heat of the flame, so when the liquid phase is away from the flame (because the flame went out, or because the liquid wax fell and now is far from the flame) the wax will cool down, and return to the solid phase.
Then we must have:
Presence of heat to go from solid to liquid.
Absence of heat to go from liquid to solid.
And we have a flame, then we must have presence of oxygen.
Then the correct option is:
A. I,II and III
