The correct answer is b. Security log monitoring.
Detective controls are meant to identify and detect security incidents or breaches after they have occurred. Security log monitoring helps in analyzing security logs to detect suspicious activities or breaches in real-time or after they happen.
In contrast:
- a. Data encryption is a preventive control.
- c. Security awareness training is also a preventive control.
- d. Access control mechanisms are preventive controls aimed at restricting access to resources.