Which is NOT a service desk type described in the ITIL service operation guidance?

Local is a valid ITIL service desk type, where a desk is situated within or physically close to the user community it serves.

Centralized is a valid ITIL service desk type, consolidating multiple local desks into a single function to reduce costs and improve consistency.

Outsourced is a sourcing strategy, not a service desk structural type recognized in ITIL Service Operation guidance. ITIL defines service desk types based on their physical and logical organization - Local (on-site per location), Centralized (single location serving multiple areas), and Virtual (geographically dispersed but appearing as one). Outsourcing describes who runs the desk, not how it is structured.

Virtual is a valid ITIL service desk type, using technology to give the impression of a single, centralized desk regardless of where staff are located.