Which of the following could be a consequence of a security breach?

A security breach can lead to the loss of confidential data, making this the correct answer. When a breach occurs, unauthorized individuals may gain access to sensitive information, such as personal identification data, financial records, or proprietary business information. This loss can have severe implications for individuals and organizations, affecting trust, legal standing, and operational integrity.

The other options, such as enhanced system performance, improved user satisfaction, or increased software functionality, do not accurately reflect the typical outcomes of a security breach. In fact, a breach often brings about decreased performance and user dissatisfaction, as the integrity and reliability of the system are compromised. Therefore, the most accurate consequence of a security breach is indeed the loss of confidential data.