Which built-in returns a BOOLEAN value that indicated whether an objects internal ID is available?（）

A.FIND_TIMER 
B.CREATE_TIMER 
C.SET_TIMER 
D.DELETE_TIMER 
E.GET_APPLICATION_PROPERTY

A.SQLCODE in an On-Error trigger. 
B.SQLCODE in an exception handler. 
C.DBMS_ERROR_CODE in an On-Error trigger. 
D.DBMS_ERROR_CODE in an exception handler.