You are the network administrator for The network consists of a single Active Directory domain named All servers run Windows Server 2003. A server named TestKing7 runs Microsoft SQL Server and hosts several mission critical databases. TestKing7 contains a mirrored volume. A routine review of TestKing7 shows failed redundancy on the mirrored volume. TestKing7 is still running and the databases are still functioning correctly. You need to correct the error and restore redundancy. What should you do first?（）

A. Initialize the failed disk.
B. Select the failed disk and reactivate the disk
C. Defragment the mirrored volume.
D. Perform a disk cleanup on the mirrored volume.