You administer a Windows 2008 server hosting an instance of Microsoft SQL Server 2012 Standard Edition. The server hosts

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You administer a Windows 2008 server hosting an instance of Microsoft SQL Server 2012 Standard Edition. The server hosts a database named Orders.
Users report that a query that filters on OrderDate is taking an exceptionally long time. You discover that an index named IX_OrderDate on the CustomerOrder table is heavily fragmented.
You need to improve the performance of the IX_OrderDate index. The index should remain online during the operation.
Which Transact-SQL command should you use?

A. ALTER INDEX IX_OrderDateON CustomerOrderDISABLE
B. ALTER INDEX IX_OrderDateON CustomerOrderENABLE
C. ALTER INDEX IX_OrderDateON CustomerOrderREORGANIZE
D. ALTER INDEX IX OrderDateON CustomerOrderREBUILD