Your database instance is functional for the past one month. The Automatic Workload Repository（AWR） snapshot retention is set to 7 and the STATISTICS_LEVEL initialization parameter is set to TYPICAL.  You receive a complaint about the poor performance of the database between 7 PM and 9 PM of theprevious day.  Choose two actions any of which can be referred to first to diagnose the problem. （）

• A、Use the Active Session History report.
• B、Use the AWR Compare Periods report.
• C、Use an ADDM analysis between 7 PM and 9 PM of the previous day.
• D、Use the AWR Compare Period report between 7 PM and 9 PM of the previous day.