You have an Exchange Server 2010 organization.  You have a group named Help Desk that contains all the help desk users in the organization.  You need to ensure that the Help Desk group can manage all the mailboxes and mail-enabled contacts in the organization.  The solution must minimize the number of permissions assigned to the Help Desk group.  Which management role should you assign to the Help Desk group？（）

• A、Mail Recipients
• B、Mail Recipient Creation
• C、Organization Client Access
• D、Recipient Policies