In the following passage some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.

The ___(1)__ of energy in India are met from both commercial and non commercial sources. The most __(2)___ sources of energy today are coal and natural gas, hydro electricity and nuclear power. On the other hand, firewood, cow-dung cakes and vegetable waste etc. ___(3)__ non commercial forms of energy. While non commercial forms of energy __(4)___ demand, coal is the __(5)___ source of commercial energy in India.