Answer : The correct option is, (B) 2, 3 and 6.
Explanation :
Combustion reaction : It is a type of reaction where a hydrocarbon react with an oxygen molecule to give carbon dioxide, water as a product.
In general,

For example : Ethane react with oxygen to give carbon dioxide and water.

In the given list,
is a reactant and
are the products.
Therefore, the correct answer is, (B) 2, 3, and 6
Explanation:
hydrogen + oxygen---> water
Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.