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 _____ of energy in India are met from both commercial and non commercial sources. The most _____ 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. _____ non commercial forms of energy. While non commercial forms of energy _____ demand, coal is the _____ source of commercial energy in India.