You work as the Exchange administrator at Company.com.The Company.com network contains an Exchange Server 2010 Organization.The organization contains the subsequent servers： the Company.com organization contains one mailbox database as well as one public folder database.You receive an instruction from the cio to ensure that in the event of -ex03 failure the public folders will remain available.What should you do？（）

A. You should consider creating a database availability group （DAG）. Thereafter -ex03 and mbx2 should be added to the dag.
B. You should consider creating a public folder database on -ex04.Thereafter the replication settings should be changed on every public folder.
C. You should consider creating a public folder database on -ex04.Thereafter the replication settings should be changed on the public folder database.
D. You should consider creating a Failover Cluster.Thereafter -ex03 and -ex04 should be added to the failover cluster.