You have created a baseline metric， DISK_IO_BL， for the disk I/O metrics in your PROD database and you have been getting notifications whenever the database performance degrades. You optimize the database I/O to gain the performance and you decide to remove the baseline metrics. Which method would you use to remove the DISK_IO_BL baseline metrics？（）

A. The baseline， once created， cannot be removed.

B. isable the baseline metrics in the Database Control Manage Metrics page.

C. The baseline will be automatically removed once the database performance has been optimized.

D. rop the baseline metrics by usingDBMS_WORKLOAD_REPOSITORY.DROP_BASELINE procedure.