What is the output of the following SQL query?
Select * from student S where not exists (select * from course C where C.ID= S.ID and C.GRADE > 40)
(a) Displays all students who never got a grade above 4.0
(b) Displays all students who never got a grade less than equal to 40
(c) Displays all students who got a grade above 4.0
(d) Displays all students who got a grade less than 4.0
How is option A and D different?