UGC NET Dec-2020 and June-2021 Paper-2

Given the following STUDENT-COURSE scheme:
STUDENT(Rollno, Name, courseno)
COURSE (courseno, coursename, capacity),
where Rollno is the primary key of relation STUDENT and courseno is the primary key of relation COURSE. Attribute coursename of COURSE takes unique values only. Which of the following query(ies) will find total number of students enrolled in each course, along with its coursename.
A. SELECT coursename, count(*) ‘total’ from STUDENT natural join COURSE group by coursename;
B. SELECT C.coursename, count(*) ‘total’ from STUDENT S, COURSE C where S.courseno=C.courseno group by coursename;
C. SELECT coursename, count(*) ‘total’ from COURSE C where courseno in (SELECT courseno from STUDENT);