What is a data breach in the context of cybersecurity?

A data breach refers to an incident where sensitive, protected, or confidential data is accessed or disclosed without authorization. This can involve various forms of sensitive information, including personal identification details, financial records, or corporate data. When such an event occurs, it poses significant risks to individuals and organizations, including identity theft, financial loss, and damage to reputation.

Understanding this definition helps establish why the correct answer is A. It directly captures the essence of a data breach, emphasizing the unauthorized access to data, which is crucial in cybersecurity incidents.

In contrast, the other options address different concepts within the cybersecurity realm. For example, software designed to protect data refers more to protective measures rather than breaches. Methods of data encryption are strategies to secure data, preventing breaches from occurring in the first place. Lastly, a formal investigation into data theft is a response to a breach but does not define what a breach itself is. Recognizing the implications of data breaches is essential for implementing effective cybersecurity strategies and protocols.