Answer : The correct option is,

Explanation :
Balanced chemical reaction : It is defined as the number of atoms of individual elements present on reactant side must be equal to the product side.
The given unbalanced chemical reaction is,
These chemical reactions are the unbalanced reactions because in this reaction, the number of atoms of individual elements present on reactant side are not equal to the product side.
Thus, the balanced chemical reaction will be,

This chemical reaction is a balanced chemical reaction because in this reaction, the number of atoms of individual elements present on reactant side are equal to the product side.