This scenario highlights a common conflict in multi-admin environments known as 'the last delivery wins' problem. When multiple administrators work in isolated sandboxes, they are essentially working on different versions of the same metadata. If Admin A adds a field to a Page Layout and deploys it, and then Admin B---who does not have Admin A's changes in their sandbox---deploys their own version of that same Page Layout, Admin B's deployment will overwrite Admin A's changes in Production (Statement B). In the Metadata API (which Change Sets use), Page Layouts are treated as single files; you cannot 'merge' them via a Change Set; you can only replace the destination file entirely.

To resolve this, the team needs a more sophisticated deployment pipeline. Statement D is the correct resolution: the company should implement a 'Staging' or 'Integration' sandbox. In this model, all admins deploy their Change Sets to a single unified sandbox first. This allows them to identify conflicts and 'merge' their changes (manually or via source control) before a final, combined deployment is made to Production. Statement A is technically incorrect because Change Sets cannot 'delete' components; they can only overwrite or add. Statement C is a myth; Page Layouts can be safely deployed, but only if the underlying fields and security settings are also included and coordinated.