基于这样的三个表即学生表S、课程表C和学生选课表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 SELECT 语句是 。
A.
SELECT S# FORM SC WHERE C#=“C2” AND GRAD>= (SELECT GRADE FORM SC WHERE C#=“C2”)
B.
SELECT S# FORM SC WHERE C#=“C2” AND GRADE IN (SELECT GRADE FORM SC 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”)