This question is really testing ownership of the feature. In this case, Choose A. Web-to-case. The Platform App Builder role is to choose the standard Salesforce capability that owns the behavior: data structure, access, automation, user experience, reporting, or deployment.
The stem gives enough detail to reject surface-level fixes. Salesforce should be configured so the behavior is enforced or rendered by the feature designed for it. When the requirement touches Business Logic and Process Automation, the builder should avoid crossing into a different layer unless there is a real platform limitation. The selected answer follows that discipline and creates the least surprising result for admins and users.
The other options fall short for clear platform reasons. B (Outbound message) handles a different concern; it handles only part of the requirement and leaves the controlling Salesforce behavior unresolved. C (Screen flow) is less defensible because Flow is broad, but it is not correct unless the requirement is specifically about guided or automated logic. D (Email-to-case) should be rejected because it works at the wrong scope for the object, field, page, automation, or deployment condition in the stem. Before release, test the configuration with the affected profile and realistic records, not only with a system administrator account.
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