You are the network administrator for TestKing.com. The network consists of a single Active Directory domain named testking.com. All network servers run Windows Server 2003. You create an organizational unit (OU) named Engineering, which will hold all objects associated with the users and computers in the engineering department. You also create a global group named Engineering Admins, whose members will administer these objects. Now you need to assign the appropriate permissions to the Engineering Admins group so its members can administer the objects in the Engineering OU. First, you use Active Directory Users and Computers to view the properties of the Engineering OU. However, the Security tab is not available. What should you do next?（）