You have an Exchange Server 2010 organization.  You plan to delegate administration of the organization.  You have a group named Technicians that contains all the level-two technicians in the organization. You need to ensure that the Technicians group can manage the properties of all the mailbox databases. The solution must minimize the number of permissions assigned to the Technicians group.  Which management role should you assign to the Technicians group？（）

• A、Help Desk
• B、Organization Management
• C、Recipient Management
• D、Server Management