Question

Coal, petroleum and natural gas are _ _ _ _ _ _ _ sources of energy.
A. convectional
B. non-conventional
C. renewable
D. all of the above

Answer 1

Hint: Conventional sources of energy are renewable sources of energy that are replenished naturally. Non-conventional sources of energy are non-renewable sources of energy that do not get replenished easily.

Complete answer:
Renewable resources of energy are those, which are replenished naturally while non-renewable resources are those which are limited and may become extinct if used without care. Classifying the sources as such gives us an insight into the limitations in using certain resources which are available to us in short supply.
Coal, petroleum, natural gas etc. are some of the resources of energy which do not get replenished as frequently as they are consumed and hence their use has to be regulated and limited and are classified under non-renewable resources.
Renewable resources are those which are available to use at such a large amount and/or are replenished regularly. Examples of non-renewable sources are solar energy, tidal energy, geo-thermal energy, wind energy etc.
Therefore, coal, petroleum and natural gas are non-renewable and non-conventional sources of energy.

So, the correct answer is “Option B”.

Note:
As mentioned before, not all sources of energy are sustainable and available to us infinitely. And hence, their usage has to be regulated if they are to be conserved for future generations and alternate sources have to be discovered.