You are a messaging professional. Your company is upgrading a Microsoft Exchange Server 2003 messaging system to a Microsoft Exchange Server 2007 messaging system.

Four Exchange Server 2007 Mailbox servers host all user mailboxes. Two Hub Transport servers and one Client Access Server have been deployed.

Two computers that run Exchange Server 2003 host public folders. Replicas of all public folders exist on both public folder servers.

Users access their mailboxes by using Microsoft Office Outlook 2007 and Microsoft Outlook Web Access (OWA).

The company has the following requirements:

A single-server failure must disrupt OWA services for the fewest number of users.

A single-server failure must disrupt access to free/busy information for the fewest number of users.

You need to implement a high availability solution that meets the requirements.

What should you do to implement a high availability solution that meets the requirements?

A.
Implement Clustered Continuous Replication (CCR) for the Mailbox servers. Move the mailboxes to the
Clustered Mailbox server.

B.
Implement a Single Copy Cluster (SCC) for the Mailbox servers. Create a public folder database on the
Clustered Mailbox server. Create a replica of the system public folders on this database.

C.
Deploy a second Hub Transport server. Configure an additional MX record for the new Hub Transport server.

D.
Deploy a second Client Access Server. Implement a Network Load Balancing (NLB) cluster for the Client
Access Servers. Set the availability Web service URL to the NLB cluster name.