Which tool should you use?

Your company has a Microsoft Exchange Server 2010 Service Pack 1 (SP1) organization and a hybrid deployment of office 365. All mailboxes are hosted on Office
365. All user accounts are hosted on-premises. You need to delete a user account and its associated mailbox.
Which tool should you use?

A.
the Exchange Control Panel

B.
the Set-Mailbox cmdlet

C.
the Remove-MailUser cmdlet

D.
Active Directory Users and Computers