In ServiceNow, ingesting custom CIs must be done with a strong focus on upgrade safety, governance, and long-term maintainability. Data Foundations guidance explicitly discourages repurposing or overloading base classes, as this creates technical debt and upgrade risk.

Option B is a best practice because the CMDB CI Class Models Store delivers ServiceNow-supported CI classes that align with platform evolution. Before creating or extending classes, administrators should verify whether a suitable class already exists or has been introduced in newer releases. This avoids duplication and ensures future compatibility.

Option D is also correct. When no suitable class exists, extending an existing CI class (under the appropriate parent) to add required attributes preserves inheritance, discovery behavior, reporting, and upgrade compatibility. This approach is preferred over creating entirely new, disconnected schemas.

Option A is incorrect because repurposing base classes and renaming attributes breaks standard semantics, causes confusion, and complicates upgrades. Option C is incorrect because extending Asset tables to represent CIs conflates ITAM and CMDB concerns; assets and CIs serve different purposes and lifecycles.

Therefore, the solutions that minimize technical debt and ensure upgrade compliance are B and D.