设有关系模式W(C, P, S, G, T,R)，其中各属性的含义是：C为课程、P为教师，S为学生，G为成绩，T为时间，R为教室，根据定义有如下函数依赖属性：
F=C'G,(S,C)'G,(T,R)'C,(T,P)'R,(T,S)'R
则W的规范化程度最高达到______。

A．SELECT Sno，AVG(Grade)
FROM SC
WHERE AVG(Grade)＞=90
GROUP BY Sno
B．SELECT Sno，AVG(Grade)
FROM SC
GROUP BY Sno
HAVING AVG(Grade)＞=90
C．SELECT Sno，AVG(Grade)
FROM SC
WHERE AVG(Grade)＞=90
ORDER BY Sno
D．SELECT Sno，AVG(Grade)
FROM SC
GROUP BY Cno
HAVING AVG(Grade)＞=90

A．活锁
B．死锁
C．排他锁
D．共享锁