How is it possible that the atomic number increases in order, yet the atomic masses do not?

A. There is no relationship between the atomic number and mass of the atom.

B. The masses of the protons for Te, I, and Xe have slightly different masses.

C. Since the numbers of neutrons do not necessarily increase from one atom to the next, it is possible for the atomic number to increase while the total mass does not increase.

D. A and B are both correct.

E. B and C are both correct.