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(SNO,SNAME,SSEX,SAGE,SDEPT),C(CNO,CNAME),SC(SNO,CNO,GRADE),其中:SNO为,SNAME为姓名,SSEX为性别,SAGE为年龄,SDEPT为系别,CNO为课程号,CNAME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。正确的SELECT语句的( )。
A.
SELECT SNO FROM SC WHERE CNO=’C2’AND GRADE>=(SELECT GRADE FROM SC WHERE CNO='C2')
B.
SELECT SNO FROM SC WHERE CNO=’C2’ AND GRADE IN (SELECT GRADE FROM SC WHERE CNO='C2')
C.
SELECT SNO FROM SC WHERE CNO=’C2’ AND GRADE NOT IN (SELECT GRADE FROM SC WHERE CNO='C2')
D.
SELECT SNO FROM SC WHERE CNO=’C2’ AND GRADE>=ALL (SELECT GRADE FROM SC WHERE CNO='C2')