View the Exhibit to examine the output of the DBA_OUTSTANDING_ALERTS view. After 30 minutes， you executed the following command：  SQL> SELECT reason，metric_value FROM dba_outstanding_alerts； REASON         METRIC_VALUE  ------------------------------------------------------------  ------------  Tablespace [TEST] is [28 percent]full  28.125  What could be the reason for the elimination of the other rows in the output（）

A、An Automatic Workload Repository snapshot has been taken recently.

B、The non-threshold-based alerts are transferred to DBA_ALERT_HISTORY.

C、The threshold alerts conditions are cleared and the alerts are transferred to DBA_ALERT_HISTORY.

D、The threshold alerts related to database metrics are permanently stored in DBA_ALERT_HISTORY but not the threshold alerts related to instance metrics.