假定有三个关系，学生关系S、课程关系C和学生选课关系SC，它们的结构如下：S(S#, SN, Sex, Age, Dept), C(C#, CN), SC(S#, C#, Grade)。其中，S#为学生号，SN为姓名，Sex为性别，Age为年龄，Dept为系别，C#为课程号，CN为课程名，Grade为成绩。检索选修课程“C2”的学生中成绩最高的学生的学号，正确的SQL语句是______。

A. SELECT S# FROM SC
WHERE C# = "C2" AND Grade IN
SELECT Grade FROM SC WHERE C# = "C2")
B. SELECT S# FROM SC
WHERE C# = "C2" AND Grade ＞=
SELECT Grade FROM SC WHERE C# = "C2")
C. SELECT S# FROM SC
WHERE C# = "C2" AND Grade ＞= ALL
SELECT Grade FROM SC WHERE C# = "C2")
D. SELECT S# FROM SC
WHERE C# = "C2" AND Grade NOT IN
SELECT Grade FROM SC WHERE C# = "C2")