In ServiceNow, protecting CMDB data quality during ingestion is a core Data Foundations principle. The Identification and Reconciliation Engine (IRE) is designed to ensure that CI records are uniquely identified, merged correctly, and protected from unauthorized overwrites. Any ingestion method that bypasses IRE introduces a high risk of duplicates and data corruption.

IntegrationHub ETL is the recommended method because it is natively designed to work with the Identification and Reconciliation API. When properly configured, IntegrationHub ETL ensures that incoming data is processed through IRE, applying identification rules, reconciliation rules, and source precedence. This allows multiple data sources to coexist safely while maintaining CMDB integrity.

Option B (Table API) is explicitly discouraged for CMDB ingestion because it writes directly to CMDB tables and bypasses IRE entirely, making it one of the most common causes of duplicate and conflicting CI records. While REST and SOAP APIs are powerful, they are not safe for CMDB ingestion unless they explicitly invoke the IRE API, which most generic table integrations do not.

Option C (Import Sets and Transform Maps) can be configured to call IRE, but this requires additional scripting and strict governance. Because of this complexity and higher risk of misconfiguration, it is not the recommended approach when safer, purpose-built options exist.

Therefore, IntegrationHub ETL is the verified and best-practice answer, making Option A correct.