The correct answer to this open question is the following.
You forgot to include the context of the question and the options too.
However, doing some research, we can comment on the following.
Betty made the decision to inform John about the medical files of the patients. So yes, Betty's actions constitute a HIPAA privacy rule violation. The reason is that Jhon did not have to have the whole files or the full level of information about the patients to do his job.
It does not matter that Betty and Jhon are friends, work together, and have adjacent cubicles. Betty is the supervisor, has access to that critical information, and should never have shared the files to John because he did not need that delicate information.