The purest form of carbon is

• coal tar

• coal gas

• coke

• none of the above

The least polluted fuel is

• petrol

• coal

• kerosene oil

• CNG

The natural solid fuel is

• coal

• coke

• LPG

• charcoal

An exhaustible natural resource is

• water

• air

• sun light

• coal

The product obtained by destructive disillation of coal is

• coal tar

• coke

• coal gas

• all of the above