student (rollno, name, degree, year, sex, deptno, advisor)
department (deptid, name, hod, phone)
professor (empid, name, sex, startyear, deptno, phone)
course (courseid, cname, credits, deptno)
enrollment (rollno, courseid, sem, year, grade)
teaching (empid, courseid, sem, year, classroom)
prerequisite (precourseid, courseid)

Given the query
SELECT s.rollno, s.name FROM student s WHERE EXISTS (SELECT c.courseid FROM course c WHERE c.deptno = 5 AND EXISTS (SELECT e.* FROM enrollment e WHERE e.courseid = c.courseid AND e.rollno = s.rollno));
which statement is correct?

1. AIt retrieves students who have not enrolled in all courses offered by department 5.
2. BIt retrieves students who have enrolled in all courses offered by department 5.
3. CIt retrieves students who have enrolled in at least one course offered by department 5.
4. DIt retrieves students for whom there exists at least one course of department 5 that they have not enrolled in.

Pick an option to check yourself, or open the answer below.