The Mass of a Particular Isotope Is Given by ________ $\times$

The mass of a particular isotope is given by ________

A) the mass number.
B) adding the masses of protons, neutrons, and electrons.
C) measuring it.
D) dividing the mass number by 6.02 $\times$ 10²³.
E) dividing the molar mass of the element by 6.02 $\times$ 10²³.