To generate recommendations to improve the performance of a set of SQL queries in an application， you execute the following blocks of code：   BEGIN  dbms_advisor.create_task（dbms_advisor.sqlaccess_advisor，’TASK1’）；  END； /  BEGIN  dbms_advisor.set_task_parameter（’TASK1’，’ANALYSIS_SCOPE’，’ALL’）； dbms_advisor.set_task_parameter（’TASK1’，’MODE’，’COMPREHENSIVE’）；  END；  /  BEGIN  dbms_advisor.execute_task（’TASK1’）；  dbms_output.put_line（dbms_advisor.get_task_script（’TASK1’））；  END；  /  The blocks of code execute successfully；however，you do not get the required outcome.  What could be the reason？（）  

• A、 A template needs to be associated with the task.
• B、 A workload needs to be associated with the task.
• C、 The partial or complete workload scope needs to be associated with the task.
• D、 The type of structures （indexes， materialized views， or partitions） to be recommended need to be  specified for the task.