Examine the description of the MARKS table:<br /> STD_ID NUMBER(4)<br /> STUDENT_NAME VARCHAR2(30)<br /> SUBJ1 NUMBER(3)<br /> SUBJ2 NUMBER(3)<br /> SUBJ3 NUMBER(3)<br /> SUBJ1, SUBJ2, and SUBJ3 indicate the marks (grades) obtained by a student in the three subjects. Which two statements are valid? ()
A、SELECT SUM(subj1, subj2, subj3) FROM marks;
B、SELECT SUM(subj1 + subj2 + subj3) FROM marks;
C、SELECT SUM(subj1), SUM(subj2), SUM(subj3) FROM marks;
D、SELECT MAX(subj1, subj2, subj3) FROM marks;
E、SELECT MINIMUM(subj1) FROM marks;
F、SELECT COUNT(std_id) FROM marks WHERE subj1 >= AVG(subj1);