Final answer:
Monitoring is used to keep subjects accountable for their actions while they are authenticated to a system.
Step-by-step explanation:
The correct answer is B. Monitoring.
Monitoring is used to keep subjects accountable for their actions while they are authenticated to a system. It involves tracking and observing the activities of authenticated users to ensure they are following the rules and policies of the system. This can be done through various methods such as log analysis, real-time alerting, and periodic audits.
For example, a system administrator may monitor a company's network to detect any unauthorized access attempts or suspicious activities by employees. This helps ensure that employees are being responsible and adhering to the company's security protocols.