This is a governance decision before it is a configuration click. The proper configuration is B. Add a rich text component to the Case Lightning page Set the component visibility of the rich text component to when the account support level is Platinum. Create a text-only custom Lightning Web Component Drag the custom Lightning Web Component into the Case page layout. In Salesforce terms, this is a Lightning page configuration issue. Lightning App Builder controls page composition, component visibility, activation, assignments, and specialized surfaces such as record pages, home pages, and utility bars.
The selected configuration is the professional answer because it is native, declarative, and placed at the right scope. If the requirement later expands, another administrator can inspect the same metadata area and understand how the behavior is being produced. That is far better than a solution that depends on hidden assumptions or user training.
The rejected choices solve different problems. A (Clone the Case Lightning page. Add a rich text component to the new page, and assign this page to platinum accounts.) is less defensible because A Lightning component changes the interface; it does not automatically solve security, relationship, or data-quality requirements. C (Set its visibility to when the account support level is platinum. Create a text-only custom Lightning Web Component. Clone the case page layout.) would be fragile here because Page layouts affect presentation; they do not grant the underlying object or field capability by themselves. D (Drag the custom Lightning Web Component into the page, and assign the layout to platinum cases.) does not fit cleanly; A Lightning component changes the interface; it does not automatically solve security, relationship, or data- quality requirements. The configuration remains understandable for future admins because the decision is visible in metadata rather than buried in a workaround.
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