Both assertion and reason are correct and the reason is the correct explanation for the assertion.
Both assertion and reason are correct but the reason is not the correct explanation for the assertion.
Assertion is correct but the reason is incorrect.
Assertion is incorrect but the reason is correct.
Solution:Combustion is a chemical reaction. There is a change in chemical composition and this reaction cannot be reversed as carbon dioxide cannot be converted into coal again. Hence, the burning of coal is a chemical change.