$[21$ Marks$]$ Specify the following queries in SQL on the database schema of Figure $1$

$($a$)[7$ marks$]$ For each department in the university that has more than $1000$ students enrolled on it$,$ get the name

of the department and the number of students enrolled in this department.

$($b$)[7$ marks$]$ Retrieve the names of students who took all the courses taught by the instructor whose name is

Smith.

$($c$)[7$ marks$]$ Retrieve the names of all students who have two majors $($i$.$e$..$ double major students$).$