The major CTS functions represented by the options are trace recording, trace query, and trace transfer , making A, B, and D correct.

Trace recording captures operations performed through the Huawei Cloud management console, through APIs, and operations initiated by supported cloud services. These records provide an audit trail containing information such as the operator, operation time, resource, operation result, and associated request data.

Trace query allows administrators and auditors to search recent operational records on the CTS console using criteria such as trace source, resource type, operator, trace status, and operation type. This is essential for security auditing, compliance investigation, and troubleshooting.

Trace transfer provides longer-term retention and centralized analysis. CTS can package operation records into trace files and transfer them to supported destinations such as OBS or LTS for preservation and subsequent processing.

Option C, OS monitoring , does not belong to CTS. Operating-system performance monitoring is primarily a Cloud Eye/server-monitoring capability rather than an audit-trace function.

Huawei's official CTS documentation expressly identifies recording, querying, and transfer among its core service functions.

Reference topics: Cloud Trace Service; Trace Recording; Trace Query; Trace Transfer; Cloud Auditing.

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