The Distinction Between an "Element" and an "Isotope" Is

Multiple Choice

The distinction between an "element" and an "isotope" is

A) an element has a specific number of neutrons; an isotope has a specific number of both protons and neutrons.
B) an element has a specific number of protons; an isotope has a specific number of neutrons.
C) an element has a specific number of protons; an isotope has a specific number of both protons and neutrons.
D) an element has a specific number of both protons and neutrons; an isotope has a specific number of protons.
E) these two words have the same meaning, but "element" is used by chemists while "isotope" is used by physicists.