The correct option is B The Assertion and the Reason are correct but the reason is not the correct explanation of the Assertion
In a chemical reaction, the reactants come in contact with each other, bonds between atoms of the reactants are broken, and these atoms rearrange and form new bonds to form products.
Thus, atoms cannot be created nor destroyed in a chemical reaction only rearrangement of atoms takes place.
So, the assertion and the reason are both correct but the reason is not the correct explanation for the assertion.