A template author needs the generated response to include the referring clinic's phone number, which is stored as a field on the Account record associated with the Case, one hop away from the Case record the template runs against. Which grounding approach correctly reaches that value?

A related-record or related-field merge reference is correct because Prompt Builder’s merge-field grounding can traverse a known relationship, such as from a Case to its associated Account, and retrieve the Account’s phone field one hop away. A vector retriever configured against the Account object’s page layout is intended for semantic search over unstructured or loosely structured content, not for retrieving one specific, known field through a structured relationship. An Apex trigger runs in response to a record data change and is an automation mechanism, not a way to ground a template at read time. Copying the clinic number onto the Case first is unnecessary: merge references can access fields on a related Account, so the claim that they cannot traverse that relationship is false. An exam caveat is that related-field grounding depends on an available relationship and the template’s supported merge references; it does not mean every arbitrary path or field is automatically accessible. As a practical check, confirm that the Case’s Account relationship is populated and that the Account phone field is available to the template, then use the merge reference that follows that relationship to the phone value.