The correct response is:
B. In a nuclear reaction, the particles in the nucleus are changed, and one element is transformed into another. In a chemical reaction, electrons are exchanged from one or more substances to produce a different substance.
This statement accurately reflects the fundamental difference between nuclear and chemical reactions: nuclear reactions involve changes in the nucleus and can change one element into another, while chemical reactions involve the rearrangement of electrons and do not change the identities of the elements involved.