Which of the following is not a commercial source of energy ?

Options

A. Coal
B. Petroleum
C. Natural Gas
D. Firewood

Answer

D

Explanation

Firewood, agricultural waste (straw , etc.) and animals waste (cowdung) are the important components of non - comused in the rural area for domestic purposes - mainly cooking . Coal , petroleum products, natural gas and , electricity are the important components of commercial energy.