Wiretapping is the act of secretly intercepting and listening to communications, typically carried out through telephone lines, in order to gain unauthorized access to private conversations. It is considered a breach of confidentiality because it involves the unauthorized acquisition of sensitive information. The other options are incorrect since they do not accurately describe the act of wiretapping. 'Phishing' refers to the fraudulent attempt to obtain sensitive information by disguising oneself as a trustworthy entity in electronic communications. 'Spoofing' is the act of disguising a communication from an unknown source as being from a known, trusted source. 'Vishing' is a combination of voice and phishing, which uses telephone calls to trick individuals into providing sensitive information.