题中假定学生关系是S(S#,SN.,SEX,AGE)，课程关系是C(C#,CNAME,TEACH-ER)，学生选课关系是SC(S#,C#,GRADE)。
检索选修课程"C2”的学生中成绩最高的学生的学号，正确的SELECT语句是______。

A．SELECT S# FORM SC
WHERE C#="C2"AND GRADE＞=(SELECT GRADE FORM SC
WHERE C#="C2")
B．SELECT S# FORM SC
WHERE C#="C2"AND GRADE IN(SELECT GRADE FORM S
C．
WHERE C#="C2"C) SELECT S# FORM SC
WHERE C#="C2"AND GRADE NOT IN(SELECT GRADE FORM SC
WHERE C#="C2")
D．SELECT S# FORM SC
WHERE C#="C2"AND GRADE＞=ALL(SELECT GRADE FORM SC
WHERE C#="C2")