1. ServiceNow Product Documentation, "Domain separation and delegated administration": "Delegated administration enables service providers to delegate user administration to their customers. For example, you can grant a customer administrator the useradmin role to administer users and groups for their company." This directly supports the correct answer (B) by defining the feature in the specific context of a Service Provider.
2. ServiceNow Product Documentation, "Delegated administration": "Delegated administration allows administrators to grant specific permissions to non-administrator users. Use this capability to extend permissions to users to manage users, groups, and roles for a specific application..." This provides the general platform definition, reinforcing that the concept is about granting scoped admin rights.
3. ServiceNow Product Documentation, "Delegates": "Set up a delegate to receive and act on your behalf for tasks and approvals." This document clearly defines the functionality described in option (C) as a separate feature named "Delegates," confirming it is not "delegated administration."