The correct option is B C(s)+O2(g)→CO2(g)
To represent a chemical reaction, a chemical equation is written with the reactants on the left hand side and the products on the right hand side of an arrow, going from left to right.
A + B → C
In the given reaction, reactants are carbon in wood (solid) and oxygen (gas); which form carbon dioxide gas as the product. The chemical equation can be written as:
C(s)+O2(g)→CO2(g)