Identify which statement is true:

A. Isotopes of the same element have the same atomic number and different mass numbers.

B. Isotopes of the same element have the same number of neutrons and a different number of protons.

C. Isotopes of the same element have the same atomic number and mass number, but a different number of neutrons,

D. Isotopes of the same element have the same mass number and different atomic numbers.​