Here, DEPT table has primary key dno.
EMP has foreign key dno and also there are integrity constraints ON DELETE AND ON UPDATE CASCADE.
So, Deletion, updation, insertion will be always successful bcoz there are actions defined in other table.
But updation in EMP should refer the DEPT table. So, NOT ALWAYS SUCCESSFUL (i.e, if the tuple is not in EMP)..
So, Option (D).............