Which two statements about the SQL Management Base （SMB） are true？（） 

• A、 It contains only SQL profiles generated by SQL Tuning Advisor.
• B、 It stores plans generated by the optimizer using a stored outline.
• C、 It is part of the data dictionary and stored in the SYSAUX tablespace.
• D、 It is part of the data dictionary and stored in the SYSTEM tablespace.
• E、 It contains the statement log，the plan history，plan baselines，and SQL profiles.