The best answer is C. To provide an organized view of configuration items and their relationships.

ISACA guidance on configuration management explicitly refers to the definition of services with configuration items and their relationships, and also notes that a CMDB should include dependency data on the business processes supported by those capabilities. That is the core reason a CMDB exists: to maintain a structured understanding of configuration items (CIs), their attributes, dependencies, and relationships so that change, incident, problem, and risk management can be performed effectively.

Option A is incorrect because incident and service request tracking belongs more to service desk or IT service management tooling, not the primary purpose of the CMDB itself. Option B is incorrect because performance metrics may be associated with items, but that is not the main reason for implementing a CMDB. Option D is incorrect because a CMDB is not a backup repository.

Therefore, the correct answer is C, because the CMDB’s main value is giving the organization a reliable, organized view of configuration items and how they relate to one another.

References (Official ISACA):

ISACA Journal, Configuration Management Using COBIT 5 — includes “configuration items and their relationships.”

ISACA, Five Key Considerations for Improving IT Supply Chain Security — CMDB as a repository of technical details and dependency data.

ISACA Journal, Cyberresilience in a Societal Context — a CMDB helps know where everything is once implemented.