Answer:
C: B's identity changes, but not A's identity. The identity of an element is solely dependent on the number of protons. For example, 2 protons in an element would be Helium. But if you add or subtract protons you would get a different element like Hydrogen or Lithium. However, such a rule does not apply to electrons; adding or removing electrons would just change the charge of the element, but not the identity.