You are the network administrator for TestKing.com. The network consists of a single Active Directory domain named testking.com. The functional level of the domain is Windows 2000 native. A global group named Travelling contains 7,000 users. All of these users are assigned portable computers, which they will use to run new POSIX-compliant application. You create a global group named POSIX. For all 7,000 users in Travelling, you change the primary group to POSIX. Members of Travelling now report that they cannot access necessary domain resources. How should you solve this problem?（）

• A、Ensure that each site on your network is connected to at least one other site by a replication link that uses the SMTP protocol.
• B、Create two new global groups, Travelling1 and Travelling2. Place one half of the members of Travelling in each new group. Then place both new groups in Travelling.
• C、Remove all domain users from the Users group, and then add all domain users to the group again.
• D、Remove all users from Travelling. Change Travelling to a universal group. Add the same users to the new Travelling group.