Final answer:
The User and Viewer roles are those that will only see their own knowledge objects and objects shared with them. Admin roles have wider access to all objects. The exact permissions can vary and should be verified with system documentation.
Step-by-step explanation:
The roles that will only see their knowledge objects and those that have been shared with them are User roles and Viewer roles. In most systems, Admins typically have the ability to see all objects, regardless of who they belong to or have been shared with, because of their higher level of system privileges. Contributors may be able to create and manage their own objects, and depending on the system's permissions settings, they may also see objects shared with them. However, these definitions can vary based on the platform, so it's important to check specific system documentation for accurate role permissions.