You need to look at the electronegativity and decide wheter the difference of both of the numbers are significant enough to form a polar bond
If the density is higher than water than the object will sink
The molecules remain intact.
The answer should be A. Because the energy in gasoline is called chemical. When burned it is heat, Then to power a vehicle, it is mechanical energy. But I don't know whether the question wants to mean that the energy in the gasoline will not convert totally to the heat, so it will lose. But if think like this, when heat energy transform to mechanical, it will lose again. So I think the answer is A.