Yup. I did realize it after my reply. Thanks.
This works :

declare
type s is ref cursor;
c s;
type r is record(
FIRST_DATE DATE,
LAST_DATE DATE,
TOTAL_STUDENTS INTEGER,
COMPLETED_STUDENTS integer,
CLASS_NAME varchar2(100));
r1 r;

begin
reporting.quiz_score_report('M125Xassess-1::AS', null, 13087, null, c);
dbms_output.put_line('first_date last_date total_students completed_students class_name');
dbms_output.put_line('----------------------------------------------------------------------------');
loop
fetch c into r1;
exit when c%NOTFOUND;
dbms_output.put_line(r1.first_date || ' ' || r1.last_date || ' ' || r1.total_students || ' ' || r1.completed_students || ' ' || r1.class_name);
end loop;
end;