The correct option is Providing continuous monitoring and alerting for security incidents.

A security information and event management solution performs centralized collection and correlation of logs and events from across the environment to enable continuous monitoring and alerting for security incidents. It detects suspicious behavior, prioritizes events, and generates alerts so teams can investigate and respond. It also supports incident investigation and reporting for compliance and forensic purposes.

Encrypting sensitive data during transit is not the primary role of a SIEM. Encryption in transit is provided by network and application level controls such as TLS and VPNs and those functions are separate from log collection and event correlation.

Google Cloud Security Command Center is a specific cloud vendor product and not a generic description of a SIEM role. It may provide security visibility for Google Cloud but the question asks for the main role of a SIEM and not a product name.

Implementing identity and access management controls is a function of IAM systems. A SIEM can monitor IAM activity and alert on suspicious access, but it does not itself implement access control policies.

Full AWS Practitioner Certification Question