Which best explains why nuclear reactions release more energy than chemical reactions?

Question

Protons have a much higher mass than either neutrons or electrons.
In nuclear reactions, the electrons in the atom are not involved in the transmutation.
The forces holding the nucleus together are much stronger than the forces binding electrons to atoms.
During a chemical reaction, some of the mass of the reactants is converted to energy.

Answer 1

The forces holding the nucleus together are much stronger than the forces binding electrons to atoms.