In a nuclear reaction the mass of the products is less than the mass ... ...

 In a nuclear reaction the mass of the products is less than the mass of the reactants. This is not observed in a chemical reaction. Why not?
(A) Mass is conserved in chemical reactions, which involve only the electromagnetic force.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in 16. Atomic and Nuclear Physics