Which of the following problems is not addressed by using OAuth (Open Standard to Authorization)
2.0 to integrate a third-party identity provider for a service?

A.
Resource Servers are required to use passwords to authenticate end users.

B.
Revocation of access of some users of the third party instead of all the users from the third party.

C.
Compromise of the third party means compromise of all the users in the service.

D.
Guest users need to authenticate with the third party identity provider.