The correct answer is : A faculty member makes identifiable data about sexual behavior available to graduate students, although the subjects were assured that the data would be de-identified.
This is a breach of confidentiality and a violation of the subjects' privacy. The faculty member has broken the confidentiality agreement with the subjects by disclosing private information about the subjects to his students by making the subjects no longer anonymous but identifiable.
All the others are a violation of subjects' privacy but no breach of confidentiality has taken place as there has been no agreement of confidentiality between the researcher and the subjects.