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)检索选修课程“C”的学生中成绩最高的学生的。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”)