Which of the following is a defense to breach of confidence?

The defense to breach of confidence centered around public interest is grounded in the principle that in certain situations, the public's right to know may outweigh an individual's right to confidentiality. When information is deemed to be in the public interest, the courts may permit the disclosure of that information even if it was obtained in a confidential setting. This often applies to matters where the information reveals misconduct, corruption, or activities that have significant implications for public welfare. For instance, whistleblowing scenarios typically highlight situations where the revealing of confidential information serves a greater good, thereby justifying its disclosure under public interest considerations.

The other options do not provide a robust defense against breach of confidence. For example, asserting an unknown source does not protect the whistleblower since public interest serves as the main justification. Similarly, an assertion that the information is untrue does not negate the confidentiality attached to it if it was originally disclosed in confidence. Redacted information might not serve as a complete defense either, as the focus is typically on whether the essence of the confidential information remains intact irrespective of how it is presented. In contrast, establishing that the information is in the public interest provides a compelling reason to disclose it, aligning with legal principles that prioritize transparency and accountability.