C is correct

C is the correct answer

C is correct:
https://help.salesforce.com/s/articleView?id=000385064&type=1

The "Manage User" permission allows users to make organizational changes to user records, including internal users, which goes beyond the desired level of access for a manager responsible for creating and editing only the community users for the Partner Community.

To restrict the manager to only creating and editing community users, you should not assign them the "Manage User" permission. Instead, you should ensure that their permissions are appropriately scoped to manage only community users, typically achieved through custom profiles, permission sets, or sharing settings specific to the Partner Community.

C. The manager has been given the Manage User permission

https://help.salesforce.com/s/articleView?id=000385064&type=1