Answer: Option (c) is the correct answer.
Step-by-step explanation:
A chemical reaction is defined as the reaction that leads to formation of new substances through exchange of electrons.
For example,

Here, aluminium on displacing copper from copper chloride leads to the formation of a new compound, that is, aluminium chloride.
Hence, it shows that atoms of reactant molecules rearrange themselves to form new substances.
Thus, we can conclude that during a chemical reaction atoms of reactants rearrange to form new substances .