If you could use any source of energy for heating your food, which one would you use and why?

I would use LPG (liquefied petroleum gas) which is used as cooking gas for heating food because:

a) It has a high calorific value. It gives a lot of heat on burning.

b) It burns with a smokeless flame and hence does not cause any air pollution.

c) It does not produce any poisonous gases on burning

d) LPG does not leave behind any ash after burning