Which statement is correct about server-generated alerts?

Which statement is correct about server-generated alerts?

A.
All server-generated alerts are based on threshold levels.

B.
Alerts are not issued for locally managed tablespaces in read-only mode.

C.
The STATISTIC_LEVEL initialization parameter must be set to ALL to enable server-generated alerts.

D.
Alerts for both locally managed tablespaces and dictionary-managed tablespaces are server generated.