The 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
breach of confidentiality occurs when a certain group or individual that hold a professional relationship with certain subjects choose to leak that sensitive information to the third party without the consent of the subject. (such as make identifiable data about sexual behavior become public for graduate students without the consent of the subjects)
violation of subjects’ privacy refers to the act of invading other individual's private space or providing unwanted attention that can endanger that individual. (such as mentioning the identity of the subjects after ensuring that they would be de-identified)