Your company uses SQL Server 2005. Users report that report execution is slow. You investigate and discover that some queries do not use optimal execution plans. You also notice that some optimizer statistics are missing and others are out of date. You need to correct the problem so that reports execute more quickly. Which two Transact-SQL statements should you use?（）

A. DBCC CHECKTABLE
B. ALTER INDEX REORGANIZE
C. UPDATE STATISTICS
D. CREATE STATISTICS
E. DBCC SHOW_STATISTICS
F. DBCC UPDATEUSAGE