The most poisonous product formed by incomplete combustion of fossil fuels is(a) Carbon dioxide (b) Nitrogen dioxide(c) Carbon monoxide (d) Sulphur dioxide

Correct Answer: (c) Carbon monoxide    

Explanation: The most poisonous product formed by the incomplete combustion of fossil fuels is carbon monoxide, as it is highly toxic and can cause several health issues if we inhale this gas for a long time.