You find today’s performance of your production database to be the best ever. Therefore， you want to be notified in the future whenever the performance degrades by 10% of today’s performance. What is the first step that you would take to ensure this？（）

• A、create baseline metrics for today’s performance
• B、write the current database metrics to a database table and create a trigger to compare with future database statistics
• C、write the current database metrics to a flat file and create an operating script to compare with future database statistics
• D、write the current database metrics to a database table and create a procedure to compare with future database statistics
• E、write the current database metrics to a database table and submit a job using DBMS_JOB to compare with future database statistics