SQL views are always updateable when $\_\_\_\_\_\_\_\_.18)\_\_\_\_\_\_$

A$)$ the view is based on any number of tables, with or without

computed columns, and the INSTEAD OF trigger is defined for

the view

B$)$ the view is based on a single table with no computed columns, and

all non$-$null columns are present in the view

C$)$ the view is based on multiple tables, the update is being done on

the most subordinate table, and the rows of that table can be

uniquely identified

D$)$ A and B

E$)$ A$,$ B and C