Which tool should you use?

Your company has a hybrid deployment of Office 365. All mailboxes are hosted on Office 365. All users access their Office 365 mailbox by using a user account

that is hosted on-premises. You need to delete a user account and its associated mailbox.
Which tool should you use?

A.
The Remove-MSOLUser cmdlet

B.
The Remove-Mailbox cmdlet

C.
The Office 365 portal

D.
Active Directory Users and Computers