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（）

An Automatic Workload Repository snapshot has been taken recently.
B. The non-threshold-based alerts are transferred to DBA_ALERT_HISTOR
C. The threshold alerts conditions are cleared and the alerts are transferred to DBA_ALERT_HISTOR
D. The threshold alerts related to database metrics are permanently stored in DBA_ALERT_HISTORY but not the threshold alerts related to instance metrics.