During an appointment with his psychiatric-mental health nurse practitioner (PMHNP), a 35-year-old man makes a credible threat to murder the ex-husband of his girlfriend. Of the following, what should the PMHNP do?

Call the police to inform them of the threat.

Call the potential victim to warn him of the threat.

Call the girlfriend to warn her of the threat, so she can let her ex-husband know.

Do nothing; this would violate confidentiality.