You work as a database administrator for Certkiller .com. In your database server， the parameter PLSQL_OPTIMIZE_LEVEL has been set to 2. What would this setting achieve？（）

• A、It degrades the run time and compiler performance.
• B、It provides better run time and compiler performance.
• C、It provides better optimization of the statement during parse time.
• D、It forces the rule based optimizer to be used for statement optimization.
• E、It provides better run time performance but slightly degraded compiler performance. 
• F、It provides better run time performance but slightly degraded run time performance.