Answer: Option (D) is the correct answer.
Explanation:
In a nuclear reaction, nucleus of atom(s) is involved in the reaction whereas in a chemical reaction electrons are involved in the reaction.
Therefore, in a nuclear reaction there occurs change in mass of the atoms participating in the reaction and the products formed. This change in mass is known as mass defect.
This difference in mass is released as energy.
Hence, we can conclude that in nuclear reactions, mass is converted to energy.